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四川省南充市第一中学2020届九年级下学期第二次诊断性考试英语试题Word版含答案
南充一中2020 年春初2020 届第二次诊断考试英语试题（考试时间:120 分钟全卷满分: 150 分）第一部分: 读（共三节；满分 70 分）第一节: 完形填空（共15 小题；每小题3 分，满分45 分）先通读下列短文，弄懂大意，然后从各题所给的A、B、C、D 四个选项中，选择可以填入空白处的最佳选项。
ＡYou want to know how we helped to save our earth this week? OK. Let me tell you.First, my family tried to save electricity. We never left the lights 1 when leaving the room. We turned off the TV when nobody was watching it. Mum only used cold water in the washing machine.Second, we started recycling this week. We tried to write on 2 side of our paper, but not just on one side. We also divided our rubbish into different bags for bottles, paper and food. Mum kept the plastic shopping bags from the supermarket to use them again as rubbish bags.Third, my family started to save 3 . We stopped taking long baths and had short showers instead. We washed the toilet with used water. Mum and dad used less water to do the washing. My sister and I didn’t leave the tap running when we brushed our teeth.At last, mum and dad began to save gas. Mum used to 4 us to school, but now my sister and I started riding our bikes to school. It’s hard work but exercise!This week dad and a few of the people in his company also started to go to work in one car and share the 5 .These are great ways to help protect our environment.( ) 1. A. on B. out C. off D. in( ) 2. A. both B. all C. every D. each( ) 3. A. food B. electricity C. water D. energy( ) 4. A. carry B. drive C. show D. take( ) 5. A. cost B. value C. pay D. spendBOne day a poor man was traveling on horseback. At noon, he tied his horse to a tree and then 6 to eat something. A few minutes later, a rich man came along and tied his horse to the same tree.“P lease tie your horse to 7 tr ee,”said the poor man. “My horse is wild. It will kill yours.” 8 the rich man said, “I shall tie my horse how I want!” He tied up his horse and had lunch nearby. After a moment they heard a terrible 9 , the two horses were fighting. They went to them, but it was too 10 . The rich man’s horse was killed. “See what your horse has done!”cried the rich man. “You will have to 11 it.” And he brought the poor man before Mr. Know.Mr. Know asked the poor man some questions. But he did not 12 . At last Mr. Know sai d, “This man is dumb. He can’t spe ak.”“O h,” the rich man shouted 13 . “He can! He spoke to me when I met him.”“Are you sure?” a sked Mr. Know. “What did he _14_ ?”“He told me not to tie my horse to the same tree because his horse was wild and would kill my horse.”“O h,”said Mr. Know. “So he 15 you. Then can you expect to get money from him?”The rich man said nothing and left silently.( ) 6. A. put down B. sat down C. set down D. turned do wn( ) 7. A. other B. others C. another D. the other( ) 8. A. So B. And C. Though D. But( ) 9. A. song B. word C. bell D. noise( ) 10. A. late B. slow C. hard D. quick( ) 11. A. pay for B. look for C. care for D. wait for( ) 12. A. write B. sing C. answer D. listen( ) 13. A. quietly B. angrily C. happily D. heavily( ) 14. A. speak B. talk C. tell D. say( ) 15. A. helped B. warned C. ordered D. thankedALots of people love to keep pets, but they don’t know how to communicate with their pets. Are you one of the pet keepers? If your answer i s “yes”, here are some suggestions for you.1. Talk with your pet.Although your pet may not exactly understand your words, he can at least pick up on the tone of your words and your body language when you talk to him. For example, if you speak with him in a stern voice, he might pick up on the fact that you are unhappy with his behavior.2. Use non-verbal(非语言的) communication.Your non-verbal communication is just as important as verbal communication. Non-verbal communication is often used in training your pet to do a certain activity. For example, if you are sitting on your horse, you would use your legs and hands to command your horse to turn around. When you teach your dog to sit, you would actually combine verbal and non-verbal communication (hand signals) to give him the ‘sit’ co mmand.3. Avoid punishing your pet.Punishing your pet is never a good idea. Punishment can make your pet fearful of you and possibly lose trust and respect that he has for you. Wha t’s more, some pets, like cats, do not necessarily make the connection between your punishment and the behavior you are punishing them for.( ) 16. The Chinese meaning of the underlined word “s ter n” in this passage is probabl y“”.A. 和善的B. 严厉的C. 柔和的D. 耐心的( ) 17. You can use your to command your horse to turn around.A. legs and handsB. arms and feetC. leg and feetD. arms and hands ( ) 18. What can we know from the passage?A. The writer tells us four suggestions in the passage.B. The writer doesn’t menti on “ho rse” in the passage.C. The writer thinks it necessary to punish pets.D. Your pet cat doesn’t understand why you punish him.( ) 19. In which part of a magazine can we read the passage?A. Animal World.B. Animal Stories.C. Body Languages.D. Body Parts.( ) 20. The best title of the passage may be “_ ”.A. How to Talk with PetsB. How to Take Care of PetsC. How to Communicate with PetsD. How to Train Dogs and CatsBIn April this year, lots of bags full of small change were seen at bus stops in Tianjin. They were made for passengers to turn their notes into small change. And such an idea came from four students from Zhongbei Middle School, Tianjin.“Peop le will surely feel worried when they take a bus without coins. We just want to do something to help them,” said Wang Yongcun, 15, one of the four students.The four boys spent their whole weekend making the change bags. After that they went to see the number of the passengers at each bus stop near their school, and then chose the top six stops to put the bags.Many people think that the four boys have really done a good job. But things didn’t go as the boys thought. Two days later, they found that the money was gone, and that even the bags were taken. It really made them sad but they would not give up. Their classmates and teachers came to help them in time. They put their pocket money in bags again. And the teachers also taught them to make better change bags. They tried their best to do it.The four boys feel very happy because they have done something good for the passengers. Their warm hearts are moving. More and more people are beginning to join in the activity.( ) 21. The change bags were put .A. on the busesB.at the bus stopsC. under the desksD. near the parks( ) 22. It took the whole weekend to make the change bags.A. the parentsB. the teachersC. the passengersD. the four boys ( ) 23. Which of the following is TRUE according to the passage?A. The idea of small change bags came from four boys.B. The passengers refused to put money in the bags.C. The teachers gave up when the bags were taken.D. The small change didn’t help the passengers much.( ) 24. The Chinese meaning of the underlined word “ch ange” in the passage isA. 变化B. 替代C. 零钱D. 机会( ) 25. Wha t’s the main idea of this passage?A. Making change bags is difficult.B. Pocket money can be helpful.C. Giving help brings us happiness.D. Every coin has two sides.CE-DA World is the largest vacation resort in southern Taiwan. Besides hotels and restaurants, it has a big mall with eight floors of shopping. Many people go to E-DA to relax, shop and have fun. E-DA World Resort also has a theme park. At the theme park, people enjoy the rides, play games and make some great memories.Many theme parks have a parade(游行), and E-DA has a nice one. You can see Da-E and Donkey in the parade. They’r e two of E-DA World’s characters. Like many theme parks, the E-DA World theme park is divided into several sections. There are rides and fun things to do in each section. Each section is inside a castle. It’s the perfect place to spend a few hours if it’s too hot outside or if it starts to rain.The best part of the theme park is the rides. E-DA World has many fun rides. Some go up and down and all around. There are water rides where people get wet. There are fast and slow rides and a big swing. The Flying Theater “F eeling Taiwan” lets you fly over Taiwan to see its many beautiful sights. And be sure to play in E-DA World’big VR station1! It’s a lot of fun. There is a ride for everyone to enjoy at E-DA World.( ) 26. E-DA World has a big mall with floors of shopping.A. sixB. sevenC. eightD. nine( ) 27. After reading the passage, we can know Da-E is .A. a character in the paradeB. the name of a restaurantC. the name of the theme parkD. the manager of E-DA World( ) 28. Which of the following is NOT mentioned according to the third paragraph?A. Water ridesB. The Flying TheaterC. The VR stationD. The 5-D theater( ) 29. What is the purpose of the passage?A. To explain why people love vacation resorts.B. To invite more people to visit E-DA World.C. To advise people to do some shopping.D. To encourage young people to work for E-DA World.( ) 30. Where may you read this passage?A. In a TV showB. In a restaurant menuC. In a guidebookD. In a storybook 第三节: 阅读填空（共5 小题；每小题2 分，满分10 分）阅读短文，根据短文内容，从短文后的六个选项中选出能填入空白处的最佳选项，有一项是多余的。
2025高考英语步步高大一轮复习讲义人教版必修第一册高考题型组合练必修第一册 Unit 4 Nat
2025高考英语步步高大一轮复习讲义人教版必修第一册高考题型组合练必修第一册Unit 4Natural DisastersⅠ.阅读理解A(★)As a shift in the polar vortex(极地涡旋) swept across much of the US，many people in the country were hit with a sudden snap of cold.Heavy ice and snow coupled with fallen trees caused the outages in major cities，with companies unable to tell their customers when power will be restored.Polar vortices were noticed long ago.But the first known use of the term “polar vortex” was in a magazine in 1853.Polar vortices are present year-round，but we don’t hear about them until they cause problems.They maintain freezing temperatures at the North and South Poles by moving in tight counterclockwise patterns.Polar vortices grow stronger in winter and weaken in summer.They are kept in place at the poles by another atmospheric current called the jet stream.However，when the jet streams weaken，the cold winds of the polar vortex are pushed southwards and it is during this time that people begin to pay attention!In Texas，roads froze over，causing six traffic deaths，and many schools were shut down.People are not the only Earthlings to struggle with the cold.Crops and animals are also freezing.This could have major consequences，especially if herds of cattle die.If snow blocks cattle，the animals can’t reach basic necessities like food and fresh water.On a brighter note，some Texas cities were more prepared than others，for instance，Amarillo，which is located in North Texas，so they are more accustomed to colder temperatures.Amarillo is notable because the city was redesigned to stand up to severe winter storms.Officials have spread out fire stations to increase coverage of first responders，employed modified dump trucks for clearing ice，and upgraded civic centers to provide shelter during storms.Hopefully，other Texas cities will follow the good example set by Amarillo!1．What does the underlined word “outages” refer to in paragraph 1?A．Traffic jams. B．Power struggles. C．Power cuts. D．Traffic accidents.2．What can we learn about polar vortices?A．They grow stronger in summer. B．They are affected by jet streams.C．They were first observed in 1853. D．They move in a clockwise direction.3．What is the last but one paragraph mainly about?A．The definition of the polar vortex.B．The characteristics of the polar vortex.C．The ways to deal with the polar vortex.D．The serious impact made by the polar vortex.4．Why is Amarillo striking?A．Because it is located in the north of Texas.B．Because it has been upgraded and modernized.C．Because it has been regarded as an example to other cities.D．Because it has taken effective measures to resist winter storms.BWhat is the 15-minute city？It’s the urban planning concept that everything city residents need should be a short walk or bike ride away—about 15 minutes from home to work，shopping，entertainment，restaurants，schools，parks and health care.Supporters argue that 15-minute cities are healthier for residents and the environment，creating united mini-communities，boosting local businesses，and encouraging people to get outside walk，and cycle.Many cities across Europe offer similar ideas，but Paris has become its poster child.Mayor Anne Hidalgo has sought to fight climate change by decreasing choking traffic in the streets and fuel emissions.In 2015，Paris was 17th on the list of bike-friendly cities; by 2019，it was 8th.Car ownership，meanwhile，dropped from 60 percent of households in 2001 to 35 percent in 2019.The 15-minute city figured largely in Hidalgo’s successful 2020 re-election campaign.The idea has also gained support in the U．S.It clearly won’t work everywhere：Not every city is as centralized and walkable as Paris.Some car-dominated cities like Los Angeles and Phoenix would be hard-pressed to provide everything people need within walking distance.In addition，some urban planners argue that the 15-minute city could increase the separation of neighborhoods by income.Neighborhoods equipped with all the conveniences required by the 15-minute city also tend to have high housing costs and wealthier residents.Despite some resistance，the basic principles behind the 15-minute city are influencing planning in cities around the world，including Melbourne，Barcelona，Buenos Aires，Singapore，and Shanghai.Urban designer and thinker Jay Pitter says cities where basic needs are within walking distance create more individual freedom than needing to drive everywhere.“In a city where services are always close by，” he says，“mobility is a choice：You go where you want because you want to，not because you have to.My fight is not against the car.My fight is how we could improve the quality of life.”5．Which best describes the 15-minute city?A．Modern. B．Smart. C．Entertaining. D．Convenient.6．What’s the original intention for Paris to advocate the 15-minute city?A．To address climate issues. B．To beautify the city.C．To promote the bike industry. D．To help Hidalgo get re-elected.7．What’s some urban planners’ worry about the 15-minute city?A．It slows the city’s expansion.B．It represents a setback for society.C．It may widen the gap between neighborhoods.D．It can cause the specialization of neighborhoods.8.What’s Jay Pitter’s attitude to the concept of 15-minute city?A．Doubtful. B．Favorable. C．Critical. D．Uninterested.C(★)Earthquake forecasting is one of the most ancient skills known to mankind.From ancient Greece to the present day，countless scientists have tried to develop tools to predict earthquakes.Their attempts usually focused on searching for reliable evidence of coming quakes.However，there are many reasons why predicting quakes is so hard.“We don’t understand some basic physics of earthquakes，” said Egill，a research professor at the California Institute of Technology.Scientists have also attempted to create mathematical models of movement，but precisely predicting would require great mapping and analysis of the Earth’s crust.Other challenges include a lack of data on the early warning signs，given that these warning signs are not yet entirely understood.Actually，real earthquake prediction is very similar to the diagnosis of potential human illnesses based on observing and analyzing each patient’s signs and symptoms.As it turns out，quake prediction is extremely difficult.Many sources show that earthquake forecasting was recognized science in ancient Greece.Ancient Greeks lived very close to nature and were able to detect unusual phenomena and forecast earthquakes.The first known forecast was made by Pherecydes of Syros about 2,500 years ago：he made it as he scooped water from a well and noticed that usually very clean water had suddenly become muddy.Indeed，an earthquake occurred two days later，making Pherecydes famous.Nowadays，seismic(地震的) and remote-sensing methods are considered to have the greatest potential in terms of solving the earthquake prediction problem.Currently，Terra Seismic can identify a forthcoming earthquake with a high level of confidence.Generally，Terra Seismic does not predict a quake if the earthquake’s epicenter is located beyond a depth of 40km.Fortunately，such quakes are almost always harmless，since quake’s energy reduces before reaching the Earth’s surface.“Scientists have tried every possible method to try to predict earthquakes，” Bruneau said.“Nobody has been able to crack it and make a believable prediction.”9．What do we know about earthquake forecasting?A．Scientists have been passionate about accurately predicting earthquakes.B．As long as enough data is collected，earthquakes can be avoided.C．Mathematical models of motion can simulate and predict earthquakes.D．Scientists have fully studied the structure of earthquakes.10．How did Pherecydes successfully predict that earthquake?A．By seismic and remote-sensing methods.B．By observing unusual natural phenomena.C．By living in seismic zones throughout the year.D．By looking into data on the early warning signs.11．What was Bruneau’s opinion about the current methods of earthquake prediction? A．He strongly believed the Terra Seismic can solve the difficult problem.B．He was sure that humans could accurately predict earthquakes in the future.C．He considered it harmless to humans for an earthquake deeper than 40km.D．He thought that scientists had no reliable method to predict earthquakes.12．What is the text mainly about?A．Why do humans predict earthquakes.B．How to protect oneself during an earthquake.C．What methods can be used to forecast earthquakes.D．When to achieve accurate earthquake forecasting.Ⅱ.七选五(★)Hurricane season can be wild and unpredictable. 1 Here are some ways you can beef up your home security in hurricane weather，even if you need to move out.2 That actually does nothing to ensure your safety in the powerful winds.Sticking to hurricane shelters or plywood(胶合板) is the only way to go when it comes to protecting those points of entry in hurricane conditions.Buy sheets of plywood，measure your windows and use brackets(支架) to hold the plywood in place.Sandbags are very useful.While sandbags won’t be able to help in the extreme storm，many people will be able to prevent flooding and extensive damage to their belongings by placing sandbags. 3 Any storm water that is kept out of your home is storm water that won’t be able to damage the belongings inside your home，so sandbags are well worth having at your doorways during a hurricane.It’s important to prepare the inside of your home for strong winds and rain.But you should also keep an eye on the outside of your house，too.Trim(修剪) trees，especially dead branches，to prevent anything else that could fly through a window and cause damage during a hurricane. 4 You should also take pictures of expensive items like electronics and keep notes of their serialnumbers. 5 Also，there are always bad people out right after a storm.If the worst happens and your home is broken into right after a bad storm，having pictures and detailed notes about what was in your home prior to the hurricane will make it easier for police to track down stolen items. A．You should have a camera at home.B．It can be strong enough to resist the forceful winds.C．Making sure nothing is loose in your yard is important.D．You may see people taping windows before a hurricane comes.E．They will be able to effectively keep storm water out in many cases.F．It will aid with your insurance company if anything needs to be replaced.G．These dangerous storms can bring damage to your home and belongings.必修第一册Unit 5Languages Around the WorldⅠ.阅读理解AMost of us take the task of buying a cup of coffee for granted，as it seems simple enough.However，we have no idea just how stressful tasks like this can be for people who suffer from disabilities.That’s why it’s so heart-warming to see a story like this in which a barista (咖啡师) does something small to make life a little easier for someone who is deaf.Ibby Piracha lost his hearing when he was only two years old，and he now goes to his local cafe in Leesburg，Virginia to order a cup of coffee at least three times a week.Though all the baristas who work there have his order memorized，Ibby always writes his order on his phone and shows it to the barista.One day，however，one of the baristas did something that changed everything! After Ibby ordered his coffee，he was amazed when barista Krystal Pane handed him a note in response.“I’ve been learning sign language just so you can have the same experience as everyone else，” the note read.Krystal then asked Ibby in sign language what he would like to order.Ibby was touched that she would learn sign language just to help him feel welcome.“I was just so moved that she actually wanted to learn sign language.It is really a totally different language and it was something that she wanted to do because of me.Because I was a deaf customer.I was very，very impressed，” Ibby said.Krystal had spent hours watching teaching videos so that she could learn enough sign language to give Ibby the best customer service that she could! “My job is to make sure peoplehave the experience they expect and that’s what I gave him，” Krystal says.Ibby posted a photo of Krystal’s note online，and it quickly went viral，getting hundreds of likes and comments that praised Krystal for her kind action.1．What can we learn about Ibby Piracha from paragraph 2?A．He was born deaf. B．He lives a hard life.C．He loves to order take-out food. D．He visits the cafe regularly.2．Why did Krystal learn sign language?A．To serve Ibby better. B．To attract more customers.C．To give Ibby a big surprise. D．To make herself more popular.3．Which of the following can best describe Krystal?A．Kind and considerate. B．Honest and responsible.C．Sociable and humorous. D．Ambitious and sensitive.4．What message does the author want to convey in the text?A．Two heads are better than one. B．A small act makes a difference.C．One good turn deserves another. D．Actions speak louder than words.B(★)(2024·湖北武汉调研)When I mentioned to some friends that we all have accents，most of them proudly replied，“Well，I speak perfect English/Chinese/etc.” But this kind of saying misses the point.More often than not，what we mean when we say someone “has an accent” is that their accent is different from the local one，or that pronunciations are different from our own.But this definition of accents is limiting and could give rise to prejudice.Funnily enough，in terms of the language study，every person speaks with an accent.It is the regular differences in how we produce sounds that define our accents.Even if you don’t hear it yourself，you speak with some sort of accent.In this sense，it’s pointless to point out that someone “has an accent”．We all do!Every person speaks a dialect，too.In the field of language study，a dialect is a version of a language that is characterized by its variations of structure，phrases and words.For instance，“You got eat or not？”(meaning “Have you eaten？”) is an acceptable and understood question in Singapore Oral English.The fact that this expression would cause a standard American English speaker to take pause doesn’t mean that Singapore Oral English is “wrong”or “ungrammatical”．The sentence is well-formed and clearly communicative，according to native Singapore English speakers’ solid system of grammar.Why should it be wrong just because it’s different?We need to move beyond a narrow conception of accents and dialects—for the benefit ofeveryone.Language differences like these provide insights into people’s cultural experiences and backgrounds.In a global age，the way one speaks is a distinct part of one’s identity.Most people would be happy to talk about the cultures behind their speech.We’d learn more about the world we live in and make friends along the way.5．What does the author think of his/her friends’ response in paragraph 1?A．It reflects their self confidence.B．It reflects their language levels.C．It misses the point of communication.D．It misses the real meaning of accents.6．Why does the author use the example of Singapore Oral English?A．To justify the use of dialects. B．To show the diversity of dialects.C．To correct a grammatical mistake. D．To highlight a traditional approach.7．What does the author recommend us to do in the last paragraph?A．Learn to speak with your local dialect.B．Seek for an official definition of accents.C．Appreciate the value of accents and dialects.D．Distinguish our local languages from others’．8．What can be a suitable title for the passage?A．Everyone Has an Accent B．Standard English Is at RiskC．Accents Enhance Our Identities D．Dialects Lead to MisunderstandingⅡ.完形填空One summer night in a seaside cottage，a small boy was in bed，sound asleep.Suddenly，he felt himself 1 from bed and carried in his father’s arms onto the beach.Overhead was the clear starry sky.“Watch！” As his father spoke， 2 ，one of the stars moved.It 3 across the sky like a golden fire.And before the 4 of this could fade，another star leapt from its place，then another...“What is it？” the child asked in 5 .“Shooting stars.They 6 every year on a certain night in August.”That was all：just an 7 encounter of something magic and beautiful.But，back in bed，the child stared into the dark，with mind full of the falling stars.I was the 8 seven-year-old boy whose father believed that a new experience 9 more for a small boy than an unbroken night’s sleep.That night，my father opened a door for his child，leading him into an area of splendid10 .Children are naturally curious，but they need someone to 11 them.This art of adding new dimensions to a child’s world doesn’t 12 require a great deal of time.It simply 13 doing things more often with children instead of for them or to them.Good parents know this：The most precious gift they can give a child is to spark their flame of 14 .That night is still deeply 15 in my memory.Next year，when August comes with its shooting stars，my son will be seven.1．A.hidden B．robbed C．lifted D．kicked2．A.incredibly B．accidentally C．apparently D．actually3．A.exploded B．circled C．spread D．flashed4．A.success B．wonder C．exhibition D．discovery5．A.amazement B．horror C．relief D．delight6．A.blow up B．turn up C．show off D．give out7．A.uncomfortable B．unbearable C．undetected D．unexpected8．A.curious B．fortunate C．determined D．chosen9．A.worked B．mattered C．deserved D．proved10．A.newness B．emptiness C．freedom D．innovation11．A.protect B．challenge C．guide D．believe12．A.absolutely B．basically C．possibly D．necessarily13．A.involves B．risks C．admits D．resists14．A.hope B．faith C．curiosity D．wisdom15.A.trapped B．set C．lost D．rootedⅢ.语法填空(★)The Olympics are a series of international athletic competitions held in different countries.They’re 1. important multi-sport event that takes place every four years.For the Olympics，participants from all over the world train for years and try their best 2. (win)．Pierre Coubertin，a French man,3. (found) the International Olympic Committee (IOC) in 1894.He was once a teacher and historian.In his honor，French had the official status(地位) and 4. (prior) over other languages at the Olympics.According to the Olympic Charter，English and French are the official languages of the Olympics.Therefore，every participant needs to have their documents 5. (translate) in both languages.Besides，real-time interpretations in Arabic，German，Russian，and Spanish must be available for all sessions.The IOC has a complete guide for those 6. want to apply to these contests.French has the status of being the first official language for Olympic events and it was the language of diplomacy (外交) in the beginning.But later，more countries considered 7. (participate) in this contest.The IOC then made French and English the official languages of the Olympics.8．(actual)，more than 100 countries in the world speak English now.Besides，almost every country has made 9. a must that children learn English in schools and colleges.This 10. (influence) status has caused the IOC to make English one of the official languages.必修第一册Welcome UnitⅠ.阅读理解AThroughout all the events in my life，one in particular sticks out more than the others.As I reflect on this significant event，a smile spreads across my face.As I think of Shanda，I feel loved and grateful.It was my twelfth year of dancing，I thought it would end up like any other year：stuck in emptiness，forgotten and without the belief of any teacher or friend that I really had the potential to achieve greatness.However，I met Shanda，a young，talented choreographer(编舞者)．She influenced me to work to the best of my ability，pushed me to keep going when I wanted to give up，encouraged me and showed me the real importance of dancing.Throughout our hard work，not only did my ability to dance grow，but my friendship with Shanda grew as well.With the end of the year came our show time.As I walked to a backstage filled with other dancers，I hoped for a good performance that would prove my improvement.I waited anxiously for my turn.Finally，after what seemed like days，the loudspeaker announced my name.Butterflies filled my stomach as I took trembling steps onto the big lighted stage.But，with the determination to succeed and eagerness to live up to Shanda’s expectations for me，I began to dance.All my troubles and nerves went away as I danced my whole heart out.As I walked up to the judge to receive my first-place shining，gold trophy(奖杯)，I realized that dance is not about becoming the best.It is about loving dance for dance itself，a getaway from all my problems in the world.Shanda showed me that you could let everything go and just dance what you feel at that moment.After all the doubts that people had in me，I believed in myself and did not care what others thought.Thanks to Shanda，dance became more than a love of mine，but a passion.1．What did the author think her dancing would be for the twelfth year?A．A change for the better. B．A disappointment as before.C．A proof of her potential. D．A pride of her teachers and friends.2．How did Shanda help the author?A．By offering her financial help. B．By entering her in a competition.C．By coaching her for longer hours. D．By awakening her passion for dancing.3．How did the author feel when she stepped on the stage?A．Proud. B．Nervous. C．Scared. D．Relieved.4．What can we learn from the author’s story?A．Success lies in patience. B．Fame is a great thirst of the young.C．A good teacher matters. D．A youth is to be treated with respect.B(★)Are you a good judge of character？Can you make an accurate judgement of someone’s personality based only on your first impression of them？Interestingly，the answer lies as much in them as it does in you.One of the first people to try to identify good judges of character was US psychologist Henry F Adams in 1927.His research led him to conclude that people fell into two groups—good judges of themselves and good judges of others.Adams’s research has been widely criticized since then，but he wasn’t entirely wrong about there being two clearly different types.More on that in a moment，but first we need to define what a good judge of character is.Is it someone who can read personality or someone who can read emotion？Those are two different skills.Emotions such as anger or joy or sadness can generate easily identifiable physical signs.Most of us would probably be able to accurately identify these signs，even in a stranger.As such，most of us are probably good judges of emotion.In order to be a good judge of personality，however，there needs to be an interaction with the other person，and that person needs to be a “good target”．“Good targets” are people who reveal relevant and useful signals to their personality.So this means “the good judge” will only manifest when reading “good targets”．This is according to Rogers and Biesanz in their 2019 journal entitled “Reassessing the good judge of personality”．“We found consistent，clear and strong evidence that the good judge does exist，” Rogers and Biesanz concluded.But their key finding is that the good judge does not have magical gifts of perception—they are simply able to “detect and use the information provided by the good target”．So，are first impressions really accurate？Well，if you’re a good judge talking to a “good target”，then it seems the answer is “yes”．And now we know that good judges probably do exist，more research can be done into how they read personality，what kind of people they are—and whether their skills can be taught.5．What can we learn about Adams from paragraph 2?A．He is a good judge of character.B．He divided psychologists into two groups.C．His research result has been widely accepted.D．His research on good judges was partially right.6．What does the author think of emotion reading?A．Annoying. B．Joyful. C．Simple. D．Strange.7.Which of the following would Rogers and Biesanz agree with?A．A good target is necessary for personality judgement.B．A good target needs to get his personality reassessed.C．A good judge can provide useful signals to our personality.D．It’s possible to be a good judge just by looking at the other person.8．What does the author think future research should focus on?A．The skills of good communication. B．The features of good judges.C．The ways to read personality. D．The accuracy of first impressions.C(2023·新课标Ⅱ，C)Reading Art: Art for Book Lo v ers is a celebration of an everyday object—the book，represented here in almost three hundred artworks from museums around the world.The image of the reader appears throughout history，in art made long before books as we now know them came into being.In artists’ representations of books and reading，we see moments of shared humanity that go beyond culture and time.In this “book of books”，artworks are selected and arranged in a way that emphasizes these connections between different eras and cultures.We see scenes of children learning to read at home or at school，with the book as a focus for relations between the generations.Adults are portrayed(描绘) alone in many settings and poses—absorbed in a volume，deep in thought or lost in a moment of leisure.These scenes may have been painted hundreds of years ago，but they record moments we can all relate to.Books themselves may be used symbolically in paintings to demonstrate the intellect(才智)，wealth or faith of the subject.Before the wide use of the printing press，books were treasured objects and could be works of art in their own right.More recently，as books have become inexpensive or even throwaway，artists have used them as the raw material for artworks—transforming covers，pages or even complete volumes into paintings and sculptures.Continued developments in communication technologies were once believed to make the printed page outdated.From a 21st-century point of view，the printed book is certainly ancient，but it remains as interactive as any battery-powered e-reader.To serve its function，a book must be activated by a user: the cover opened，the pages parted，the contents reviewed，perhaps notes written down or words underlined.And in contrast to our increasingly networked lives where theinformation we consume is monitored and tracked，a printed book still offers the chance of a wholly private，“off-line” activity.9．Where is the text most probably taken from?A．An introduction to a book. B．An essay on the art of writing.C．A guidebook to a museum. D．A review of modern paintings.10．What are the selected artworks about?A．Wealth and intellect. B．Home and school.C．Books and reading. D．Work and leisure.11．What do the underlined words “relate to” in paragraph 2 mean?A．Understand. B．Paint. C．Seize. D．Transform.12．What does the author want to say by mentioning the e-reader?A．The printed book is not totally out of date.B．Technology has changed the way we read.C．Our lives in the 21st century are networked.D．People now rarely have the patience to read.Ⅱ.七选五Wonderful views from the mountains，breathtaking places waiting to explore，fresh air，as well as all the special health benefits，are the main rewards of mountain hiking. 1You need to train your lower body muscles，anytime and anywhere.Strong legs and core muscles will improve your balance and help you hike longer.Focus on your lower body strength and on your cardiovascular(心血管的) workout. 2 You really can train anywhere：use your backyard，living room，or bedroom to keep your body ready for the true conditions in the mountains.You will need a stronger back.Who’s going to carry your backpack？ 3 So we are quite sure what the true answer is.Develop back muscles with exercises like V-ups，deadlifts，diver push-ups，and exercise named “mountain climbers”：Start in a traditional plank(平板支撑) position and then bring your knee forward under your chest.You will start to feel your abs(腹肌) for sure，too.4 Even Rome wasn’t built in a day so give yourself the pleasure to enjoy discovering what your body is capable of! All the perfect benefits will improve your blood pressure and blood sugar levels，helping you strengthen your core，and even help you control your weight as an additional benefit.5 Just don’t forget to stretch after each training.Please remember that your training for mountain hiking should be combined with real hiking.And don’t miss the other clues on what to do for mountaineering training!。
餐桌礼仪英语对话【西方餐桌礼仪英语版对话阅读】
餐桌礼仪英语对话【西方餐桌礼仪英语版对话阅读】西方餐桌礼仪英语版对话阅读西方餐桌礼仪英语版对话阅读西方餐桌礼仪英语版People who go to a formal Western dinner party for the first time may be surprised by table manners in Western culture.Knowing them will help you make a good impression.Having good table manners means knowing,for example,how to use knives and forks,when to drink a toast and how to behave at the table.Beside your napkin you will find a small bread roll and three glasses—one for white wine,one for the red wine,and one for water.There are two pairs of knives and forks on the table,forks on the left and knives in the right of the plate.When you see two spoons,the big one id for the suop and the samll one for the dessert.The knife and fork that are closest to your plate are a litte bit bigger than the ones beside them.When you sit down at the table,you can take your napkin,unfold it and put it on your lap.In Chinese you sometime get a hot,damp cloth to clean your face and face and hands,whinch,however,is nat the custom in Western countries. Dinner start with a small dish,which is often called a starter.Sime people pray before they start eating ,and other people may keep silent for a moment.Then you can say“Enjoy your meal“to each other and everybody start eating.For the starter,which you eat with the smaller pair,you keep the knife in your right hand and the fork in your left.After the starter you will get a bowl of soup—but only one boel of soup and never ask for a seconf serving. The next dish is the main course.Many Westerners think the chicken breast with its tender white flesh is the best part of the bird.Some people can use their fingers when they eating chicken or other birds,but never touch beefor other meat in bones.It is polite to finish eating everthing on your plate,so don"t take more food than you need. At table ,you should try to speak quietly and smile a lot,but do not laugh all the time. Most Westerners like soft drink if they will drive home.Many of them drink white or red wine with the food.When drinking to someone"s health,you raise your glasses,but the glasses should not touch.The custom of toasting in some parts of China is to finish the drink at once,but Westerners usually take only a sip.For drinking during a dinner,the best advic is never to drink too much. Table manners change over time.They follow the fashion of the day .Beside,table manners are only important at formal dinner parties.If you"re not sure what to do ,you can always follow your hosts.Although good manners always make you look good,you do not need to worry about all these rules while having dinner with your friends or family. 英美餐桌礼仪阅读"Oh, no! Here I am at an American family"s home at the dinner table. There are all kinds of plates, saucers, cups, and silverware at my place. Which should I use for which food Should I sit down first or wait for the host to invite me Should I have brought a gift Someone please tell me what to do!" “哦，糟糕!此刻我坐在一个美国人家里的餐桌前吃晚餐。
专业英语四级(听力)模拟试卷204(题后含答案及解析)
专业英语四级（听力）模拟试卷204(题后含答案及解析)题型有： 2. LISTENING COMPREHENSIONPART II LISTENING COMPREHENSIONSECTION A TALKIn this section you will hear a talk. You will hear the talk ONCE ONLY. While listening, you may look at ANSWER SHEET ONE and write NO MORE THAN THREE WORDS for each gap. Make sure the word (s) you fill in is (are) both grammatically and semantically acceptable. You may use the blank sheet for note-taking.You have THIRTY seconds to preview the gap-filling task.听力原文： A New Approach to Debate (1)Teachers of English may hesitate to teach debate because they think it is beyond their students’ language ability, or proficiency. But debate can be a powerful tool. It can help students learn to speak naturally and to listen carefully. Professor Charles Lebeau teaches English and debate in Japan. He wrote “Discover Debate” with Michael Lubetsky. The book helps English teachers and learners understand how to carry on a simple debate. The “Discover Debate” approach has three stages: creating a visual aid to communicate an argument, presenting the argument and answering the other team’s argument. Each stage puts increasing demands on language ability. It begins with a pre-debate experience. When teaching debate to English learners, Mr. Lebeau recommends beginning with “controlled practice.”Students work in pairs to practice saying opinions and giving reasons in short conversations. (2)They learn to identify opinions and arguments about everyday topics, such as sports stars, foods, weather and habits.(3)Teachers may be tempted to give students serious topics, such as “People should stop using nuclear power.” However, Mr. Lebeau cautions that English learners may not have the necessary language ability to handle such topics. More serious topics often require special vocabulary and research. Mr. Lebeau’s classes in Japan are like many in universities; they have 40 to 50 students. (4)He has students form debate teams of three or six, depending on the total number of students. (5)Each_team creates a visual aid to show their thinking on the topic. The visual is a house: a roof represents an opinion, pillars are the reasons supporting the opinion and the foundation is the evidence. In the next stage, students present their argument. They have to do some talking, but not too much. (6)The third stage is answering the opponents’ argument. Here, debaters need a higher level of language ability. (7)Mr. Lebeau recommends pausing for the opposing team to develop their answers, or refutations. Each team might go to a different area and discuss the weak points in the opposing argument. Students must first think about the arguments carefully. In “Discover Debate,”Michael Lubetsky and Charles Lebeau include a guide to help students evaluate arguments. The evaluation also takes advantage of the visual aid of a house. (8)Students are asked to look for flaws, or problems. They identify things that are either “not true”or “not important.”(9)Students can write easilyremembered abbreviations on their opponents’ houses: “NT” for not true, “NAT” for not always true, or “NNT” for not necessarily true. These simple expressions make it easier for students to refute their opponents’arguments. Traditional debate includes several cycles of presentation and refutation. For English learners, one cycle of presentation and refutation is usually enough practice. Mr. Lebeau says sometimes he asks the rest of the class to vote on which side won. (10)Asking for audience feedback gives the lesson a good ending. But, he says, additional discussion depends on the situation and the level of the students.A New Approach to DebateI. Teachers’hesitation: debate is beyond students’【T1】______【T1】______II. Suggestions from Prof. Charles Lebeau to teachersa) Begin with controlled practice: to【T2】______opinions and arguments【T2】______b) Caution: no【T3】______topics 【T3】______III. “Discover Debate”ApproachTeam members: depending on the【T4】______of students 【T4】______The first stage: creating a【T5】______aid【T5】______The second stage: presenting argumentsThe third stage: answering the【T6】______argument 【T6】______a) Pause for the opponents to develop answers or【T7】______【T7】______b) Evaluate arguments: to look for【T8】______ . 【T8】______c) Write easily remembered【T9】______【T9】______Ending: ask for audience 【T10】______【T10】______ 1．【T1】正确答案：language ability／proficiency解析：空格前的beyond students’提示填入一个名词，表示“超出学生的……范围”。
中西餐差别英语作文【优秀3篇】
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文档下载后可定制修改，请根据实际需要进行调整和使用，谢谢!并且，本店铺为大家提供各种类型的经典范文，如合同协议、条据文书、策划方案、总结报告、党团资料、读书笔记、读后感、作文大全、教案资料、其他范文等等，想了解不同范文格式和写法，敬请关注!Download tips: This document is carefully compiled by this editor. I hope that after you download it, it can help you solve practical problems. The document can be customized and modified after downloading, please adjust and use it according to actual needs, thank you!Moreover, our store provides various types of classic sample essays, such as contract agreements, documentary evidence, planning plans, summary reports, party and youth organization materials, reading notes, post reading reflections, essay encyclopedias, lesson plan materials, other sample essays, etc. If you want to learn about different formats and writing methods of sample essays, please stay tuned!中西餐差别英语作文【优秀3篇】无论在学习、工作或是生活中，大家都有写作文的经历，对作文很是熟悉吧，作文可分为小学作文、中学作文、大学作文（论文）。
新人教版(2019) 第二册 unit1 From Problems to Solutions课件
Read for Structure
General-specific
From problems to Solutions
①Economic development is necessary if we want to
improve society. There comes a time when the old must
From Problems to Solutions
Warming-up
As the Liangzhu Cultural Sites has just been added to the The World Heritage List, the government has met a problem: how to keep a balance between developing tourism and protecting the sites.
Read for information
6. Does the writer mainly want to introduce the case of Aswan Dam with this passage?
7. Read Paragraph 1, 2 and 6, and figure out what the writer wants to tell with this passage ?
⑥The spirit of the Aswan Dam project still prevails today. etc,...
developing economy
preserving cultural sites
2. What did the government do with the problem? The government turned to the UN for help in 1959.
rfc6146.Stateful NAT64 Network Address and Protocol Translation from IPv6 Clients to IPv4 Servers
Internet Engineering Task Force (IETF) M. Bagnulo Request for Comments: 6146 UC3M Category: Standards Track P. Matthews ISSN: 2070-1721 Alcatel-Lucent I. van Beijnum IMDEA Networks April 2011 Stateful NAT64: Network Address and Protocol Translationfrom IPv6 Clients to IPv4 ServersAbstractThis document describes stateful NAT64 translation, which allowsIPv6-only clients to contact IPv4 servers using unicast UDP, TCP, or ICMP. One or more public IPv4 addresses assigned to a NAT64translator are shared among several IPv6-only clients. When stateful NAT64 is used in conjunction with DNS64, no changes are usuallyrequired in the IPv6 client or the IPv4 server.Status of This MemoThis is an Internet Standards Track document.This document is a product of the Internet Engineering Task Force(IETF). It represents the consensus of the IETF community. It hasreceived public review and has been approved for publication by theInternet Engineering Steering Group (IESG). Further information onInternet Standards is available in Section 2 of RFC 5741.Information about the current status of this document, any errata,and how to provide feedback on it may be obtained at/info/rfc6146.Bagnulo, et al. Standards Track [Page 1]Copyright NoticeCopyright (c) 2011 IETF Trust and the persons identified as thedocument authors. All rights reserved.This document is subject to BCP 78 and the IETF Trust’s LegalProvisions Relating to IETF Documents(/license-info) in effect on the date ofpublication of this document. Please review these documentscarefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e ofthe Trust Legal Provisions and are provided without warranty asdescribed in the Simplified BSD License.Bagnulo, et al. Standards Track [Page 2]Table of Contents1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1. Features of Stateful NAT64 . . . . . . . . . . . . . . . . 5 1.2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . 6 1.2.1. Stateful NAT64 Solution Elements . . . . . . . . . . . 6 1.2.2. Stateful NAT64 Behavior Walk-Through . . . . . . . . . 81.2.3. Filtering . . . . . . . . . . . . . . . . . . . . . . 102. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 113. Stateful NAT64 Normative Specification . . . . . . . . . . . . 14 3.1. Binding Information Bases . . . . . . . . . . . . . . . . 14 3.2. Session Tables . . . . . . . . . . . . . . . . . . . . . . 15 3.3. Packet Processing Overview . . . . . . . . . . . . . . . . 17 3.4. Determining the Incoming Tuple . . . . . . . . . . . . . . 18 3.5. Filtering and Updating Binding and Session Information . . 20 3.5.1. UDP Session Handling . . . . . . . . . . . . . . . . . 21 3.5.1.1. Rules for Allocation of IPv4 TransportAddresses for UDP . . . . . . . . . . . . . . . . 23 3.5.2. TCP Session Handling . . . . . . . . . . . . . . . . . 24 3.5.2.1. State Definition . . . . . . . . . . . . . . . . . 24 3.5.2.2. State Machine for TCP Processing in the NAT64 . . 25 3.5.2.3. Rules for Allocation of IPv4 TransportAddresses for TCP . . . . . . . . . . . . . . . . 33 3.5.3. ICMP Query Session Handling . . . . . . . . . . . . . 33 3.5.4. Generation of the IPv6 Representations of IPv4Addresses . . . . . . . . . . . . . . . . . . . . . . 36 3.6. Computing the Outgoing Tuple . . . . . . . . . . . . . . . 36 3.6.1. Computing the Outgoing 5-Tuple for TCP, UDP, andfor ICMP Error Messages Containing a TCP or UDPPackets . . . . . . . . . . . . . . . . . . . . . . . 37 3.6.2. Computing the Outgoing 3-Tuple for ICMP QueryMessages and for ICMP Error Messages Containing anICMP Query . . . . . . . . . . . . . . . . . . . . . . 38 3.7. Translating the Packet . . . . . . . . . . . . . . . . . . 383.8. Handling Hairpinning . . . . . . . . . . . . . . . . . . . 394. Protocol Constants . . . . . . . . . . . . . . . . . . . . . . 395. Security Considerations . . . . . . . . . . . . . . . . . . . 40 5.1. Implications on End-to-End Security . . . . . . . . . . . 40 5.2. Filtering . . . . . . . . . . . . . . . . . . . . . . . . 40 5.3. Attacks on NAT64 . . . . . . . . . . . . . . . . . . . . . 415.4. Avoiding Hairpinning Loops . . . . . . . . . . . . . . . . 426. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 437. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 438. References . . . . . . . . . . . . . . . . . . . . . . . . . . 43 8.1. Normative References . . . . . . . . . . . . . . . . . . . 43 8.2. Informative References . . . . . . . . . . . . . . . . . . 44 Bagnulo, et al. Standards Track [Page 3]1. IntroductionThis document specifies stateful NAT64, a mechanism for IPv4-IPv6transition and IPv4-IPv6 coexistence. Together with DNS64 [RFC6147], these two mechanisms allow an IPv6-only client to initiatecommunications to an IPv4-only server. They also enable peer-to-peer communication between an IPv4 and an IPv6 node, where thecommunication can be initiated when either end uses existing, NAT-traversal, peer-to-peer communication techniques, such as Interactive Connectivity Establishment (ICE) [RFC5245]. Stateful NAT64 alsosupports IPv4-initiated communications to a subset of the IPv6 hosts through statically configured bindings in the stateful NAT64.Stateful NAT64 is a mechanism for translating IPv6 packets to IPv4packets and vice versa. The translation is done by translating thepacket headers according to the IP/ICMP Translation Algorithm defined in [RFC6145]. The IPv4 addresses of IPv4 hosts are algorithmicallytranslated to and from IPv6 addresses by using the algorithm defined in [RFC6052] and an IPv6 prefix assigned to the stateful NAT64 forthis specific purpose. The IPv6 addresses of IPv6 hosts aretranslated to and from IPv4 addresses by installing mappings in thenormal Network Address Port Translation (NAPT) manner [RFC3022]. The current specification only defines how stateful NAT64 translatesunicast packets carrying TCP, UDP, and ICMP traffic. Multicastpackets and other protocols, including the Stream ControlTransmission Protocol (SCTP), the Datagram Congestion ControlProtocol (DCCP), and IPsec, are out of the scope of thisspecification.DNS64 is a mechanism for synthesizing AAAA resource records (RRs)from A RRs. The IPv6 address contained in the synthetic AAAA RR isalgorithmically generated from the IPv4 address and the IPv6 prefixassigned to a NAT64 device by using the same algorithm defined in[RFC6052].Together, these two mechanisms allow an IPv6-only client (i.e., ahost with a networking stack that only implements IPv6, a host with a networking stack that implements both protocols but with only IPv6connectivity, or a host running an IPv6-only application) to initiate communications to an IPv4-only server (which is analogous to theIPv6-only host above).These mechanisms are expected to play a critical role in IPv4-IPv6transition and IPv4-IPv6 coexistence. Due to IPv4 address depletion, it is likely that in the future, the new clients will be IPv6-onlyand they will want to connect to the existing IPv4-only servers. The stateful NAT64 and DNS64 mechanisms are easily deployable, since they do not require changes to either the IPv6 client or the IPv4 server. Bagnulo, et al. Standards Track [Page 4]For basic functionality, the approach only requires the deployment of the stateful NAT64 function in the devices connecting an IPv6-onlynetwork to the IPv4-only network, along with the deployment of a few DNS64-enabled name servers accessible to the IPv6-only hosts. Ananalysis of the application scenarios can be found in [RFC6144].For brevity, in the rest of the document, we will refer to thestateful NAT64 either as stateful NAT64 or simply as NAT64.1.1. Features of Stateful NAT64The features of NAT64 are:o NAT64 is compliant with the recommendations for how NATs shouldhandle UDP [RFC4787], TCP [RFC5382], and ICMP [RFC5508]. As such, NAT64 only supports Endpoint-Independent Mappings and supportsboth Endpoint-Independent and Address-Dependent Filtering.Because of the compliance with the aforementioned requirements,NAT64 is compatible with current NAT traversal techniques, such as ICE [RFC5245], and with other NAT traversal techniques.o In the absence of preexisting state in a NAT64, only IPv6 nodescan initiate sessions to IPv4 nodes. This works for roughly thesame class of applications that work through IPv4-to-IPv4 NATs.o Depending on the filtering policy used (Endpoint-Independent, orAddress-Dependent), IPv4-nodes might be able to initiate sessions to a given IPv6 node, if the NAT64 somehow has an appropriatemapping (i.e., state) for an IPv6 node, via one of the followingmechanisms:* The IPv6 node has recently initiated a session to the same oranother IPv4 node. This is also the case if the IPv6 node has used a NAT-traversal technique (such as ICE).* A statically configured mapping exists for the IPv6 node.o IPv4 address sharing: NAT64 allows multiple IPv6-only nodes toshare an IPv4 address to access the IPv4 Internet. This helpswith the forthcoming IPv4 exhaustion.o As currently defined in this NAT64 specification, only TCP, UDP,and ICMP are supported. Support for other protocols (such asother transport protocols and IPsec) is to be defined in separate documents.Bagnulo, et al. Standards Track [Page 5]1.2. OverviewThis section provides a non-normative introduction to NAT64. This is achieved by describing the NAT64 behavior involving a simple setupthat involves a single NAT64 device, a single DNS64, and a simplenetwork topology. The goal of this description is to provide thereader with a general view of NAT64. It is not the goal of thissection to describe all possible configurations nor to provide anormative specification of the NAT64 behavior. So, for the sake ofclarity, only TCP and UDP are described in this overview; the details of ICMP, fragmentation, and other aspects of translation arepurposefully avoided in this overview. The normative specificationof NAT64 is provided in Section 3.The NAT64 mechanism is implemented in a device that has (at least)two interfaces, an IPv4 interface connected to the IPv4 network, and an IPv6 interface connected to the IPv6 network. Packets generatedin the IPv6 network for a receiver located in the IPv4 network willbe routed within the IPv6 network towards the NAT64 device. TheNAT64 will translate them and forward them as IPv4 packets throughthe IPv4 network to the IPv4 receiver. The reverse takes place forpackets generated by hosts connected to the IPv4 network for an IPv6 receiver. NAT64, however, is not symmetric. In order to be able to perform IPv6-IPv4 translation, NAT64 requires state. The statecontains the binding of an IPv6 address and TCP/UDP port (hereaftercalled an IPv6 transport address) to an IPv4 address and TCP/UDP port (hereafter called an IPv4 transport address).Such binding state is either statically configured in the NAT64 or it is created when the first packet flowing from the IPv6 network to the IPv4 network is translated. After the binding state has beencreated, packets flowing in both directions on that particular floware translated. The result is that, in the general case, NAT64 only supports communications initiated by the IPv6-only node towards anIPv4-only node. Some additional mechanisms (like ICE) or staticbinding configuration can be used to provide support forcommunications initiated by an IPv4-only node to an IPv6-only node. 1.2.1. Stateful NAT64 Solution ElementsIn this section, we describe the different elements involved in theNAT64 approach.The main component of the proposed solution is the translator itself. The translator has essentially two main parts, the addresstranslation mechanism and the protocol translation mechanism. Bagnulo, et al. Standards Track [Page 6]Protocol translation from an IPv4 packet header to an IPv6 packetheader and vice versa is performed according to the IP/ICMPTranslation Algorithm [RFC6145].Address translation maps IPv6 transport addresses to IPv4 transportaddresses and vice versa. In order to create these mappings, theNAT64 has two pools of addresses: an IPv6 address pool (to represent IPv4 addresses in the IPv6 network) and an IPv4 address pool (torepresent IPv6 addresses in the IPv4 network).The IPv6 address pool is one or more IPv6 prefixes assigned to thetranslator itself. Hereafter, we will call the IPv6 address poolPref64::/n; in the case there is more than one prefix assigned to the NAT64, the comments made about Pref64::/n apply to each of them.Pref64::/n will be used by the NAT64 to construct IPv4-Converted IPv6 addresses as defined in [RFC6052]. Due to the abundance of IPv6address space, it is possible to assign one or more Pref64::/n, each of them being equal to or even bigger than the size of the whole IPv4 address space. This allows each IPv4 address to be mapped into adifferent IPv6 address by simply concatenating a Pref64::/n with the IPv4 address being mapped and a suffix. The provisioning of thePref64::/n as well as the address format are defined in [RFC6052].The IPv4 address pool is a set of IPv4 addresses, normally a prefixassigned by the local administrator. Since IPv4 address space is ascarce resource, the IPv4 address pool is small and typically notsufficient to establish permanent one-to-one mappings with IPv6addresses. So, except for the static/manually created ones, mappings using the IPv4 address pool will be created and released dynamically. Moreover, because of the IPv4 address scarcity, the usual practicefor NAT64 is likely to be the binding of IPv6 transport addressesinto IPv4 transport addresses, instead of IPv6 addresses into IPv4addresses directly, enabling a higher utilization of the limited IPv4 address pool. This implies that NAT64 performs both address and port translation.Because of the dynamic nature of the IPv6-to-IPv4 address mapping and the static nature of the IPv4-to-IPv6 address mapping, it is farsimpler to allow communications initiated from the IPv6 side towardan IPv4 node, whose address is algorithmically mapped into an IPv6address, than communications initiated from IPv4-only nodes to anIPv6 node. In that case, an IPv4 address needs to be associated with the IPv6 node’s address dynamically.Using a mechanism such as DNS64, an IPv6 client obtains an IPv6address that embeds the IPv4 address of the IPv4 server and sends apacket to that IPv6 address. The packets are intercepted by theNAT64 device, which associates an IPv4 transport address out of its Bagnulo, et al. Standards Track [Page 7]IPv4 pool to the IPv6 transport address of the initiator, creatingbinding state, so that reply packets can be translated and forwarded back to the initiator. The binding state is kept while packets areflowing. Once the flow stops, and based on a timer, the IPv4transport address is returned to the IPv4 address pool so that it can be reused for other communications.To allow an IPv6 initiator to do a DNS lookup to learn the address of the responder, DNS64 [RFC6147] is used to synthesize AAAA RRs fromthe A RRs. The IPv6 addresses contained in the synthetic AAAA RRscontain a Pref64::/n assigned to the NAT64 and the IPv4 address ofthe responder. The synthetic AAAA RRs are passed back to the IPv6initiator, which will initiate an IPv6 communication with an IPv6address associated to the IPv4 receiver. The packet will be routedto the NAT64 device, which will create the IPv6-to-IPv4 addressmapping as described before.1.2.2. Stateful NAT64 Behavior Walk-ThroughIn this section, we provide a simple example of the NAT64 behavior.We consider an IPv6 node that is located in an IPv6-only site andthat initiates a TCP connection to an IPv4-only node located in theIPv4 network.The scenario for this case is depicted in the following figure:+---------------------+ +---------------+|IPv6 network | | IPv4 || | +-------------+ | network || |--| Name server |--| || | | with DNS64 | | +----+ || +----+ | +-------------+ | | H2 | || | H1 |---| | | +----+ || +----+ | +-------+ | 192.0.2.1 ||2001:db8::1|------| NAT64 |----| || | +-------+ | || | | | |+---------------------+ +---------------+The figure above shows an IPv6 node H1 with an IPv6 address2001:db8::1 and an IPv4 node H2 with IPv4 address 192.0.2.1. H2 has as its Fully Qualified Domain Name (FQDN).A NAT64 connects the IPv6 network to the IPv4 network. This NAT64uses the Well-Known Prefix 64:ff9b::/96 defined in [RFC6052] torepresent IPv4 addresses in the IPv6 address space and a single IPv4 address 203.0.113.1 assigned to its IPv4 interface. The routing is Bagnulo, et al. Standards Track [Page 8]configured in such a way that the IPv6 packets addressed to adestination address in 64:ff9b::/96 are routed to the IPv6 interface of the NAT64 device.Also shown is a local name server with DNS64 functionality. Thelocal name server uses the Well-Known Prefix 64:ff9b::/96 to createthe IPv6 addresses in the synthetic RRs.For this example, assume the typical DNS situation where IPv6 hostshave only stub resolvers, and the local name server does therecursive lookups.The steps by which H1 establishes communication with H2 are:1. H1 performs a DNS query for h and receives thesynthetic AAAA RR from the local name server that implements the DNS64 functionality. The AAAA record contains an IPv6 addressformed by the Well-Known Prefix and the IPv4 address of H2 (i.e., 64:ff9b::192.0.2.1).2. H1 sends a TCP SYN packet to H2. The packet is sent from asource transport address of (2001:db8::1,1500) to a destinationtransport address of (64:ff9b::192.0.2.1,80), where the ports are set by H1.3. The packet is routed to the IPv6 interface of the NAT64 (sinceIPv6 routing is configured that way).4. The NAT64 receives the packet and performs the following actions: * The NAT64 selects an unused port (e.g., 2000) on its IPv4address 203.0.113.1 and creates the mapping entry(2001:db8::1,1500) <--> (203.0.113.1,2000)* The NAT64 translates the IPv6 header into an IPv4 header using the IP/ICMP Translation Algorithm [RFC6145].* The NAT64 includes (203.0.113.1,2000) as the source transport address in the packet and (192.0.2.1,80) as the destinationtransport address in the packet. Note that 192.0.2.1 isextracted directly from the destination IPv6 address of thereceived IPv6 packet that is being translated. Thedestination port 80 of the translated packet is the same asthe destination port of the received IPv6 packet.5. The NAT64 sends the translated packet out of its IPv4 interfaceand the packet arrives at H2.Bagnulo, et al. Standards Track [Page 9]6. H2 node responds by sending a TCP SYN+ACK packet with thedestination transport address (203.0.113.1,2000) and sourcetransport address (192.0.2.1,80).7. Since the IPv4 address 203.0.113.1 is assigned to the IPv4interface of the NAT64 device, the packet is routed to the NAT64 device, which will look for an existing mapping containing(203.0.113.1,2000). Since the mapping (2001:db8::1,1500) <-->(203.0.113.1,2000) exists, the NAT64 performs the followingoperations:* The NAT64 translates the IPv4 header into an IPv6 header using the IP/ICMP Translation Algorithm [RFC6145].* The NAT64 includes (2001:db8::1,1500) as the destinationtransport address in the packet and (64:ff9b::192.0.2.1,80) as the source transport address in the packet. Note that192.0.2.1 is extracted directly from the source IPv4 addressof the received IPv4 packet that is being translated. Thesource port 80 of the translated packet is the same as thesource port of the received IPv4 packet.8. The translated packet is sent out of the IPv6 interface to H1.The packet exchange between H1 and H2 continues, and packets aretranslated in the different directions as previously described.It is important to note that the translation still works if the IPv6 initiator H1 learns the IPv6 representation of H2’s IPv4 address(i.e., 64:ff9b::192.0.2.1) through some scheme other than a DNSlookup. This is because the DNS64 processing does NOT result in any state being installed in the NAT64 and because the mapping of theIPv4 address into an IPv6 address is the result of concatenating the Well-Known Prefix to the original IPv4 address.1.2.3. FilteringNAT64 may do filtering, which means that it only allows a packet inthrough an interface under certain circumstances. The NAT64 canfilter IPv6 packets based on the administrative rules to createentries in the binding and session tables. The filtering can beflexible and general, but the idea of the filtering is to provide the administrators necessary control to avoid denial-of-service (DoS)attacks that would result in exhaustion of the NAT64’s IPv4 address, port, memory, and CPU resources. Filtering techniques of incomingIPv6 packets are not specific to the NAT64 and therefore are notdescribed in this specification.Bagnulo, et al. Standards Track [Page 10]Filtering of IPv4 packets, on the other hand, is tightly coupled tothe NAT64 state and therefore is described in this specification. In this document, we consider that the NAT64 may do no filtering, or it may filter incoming IPv4 packets.NAT64 filtering of incoming IPv4 packets is consistent with therecommendations of [RFC4787] and [RFC5382]. Because of that, theNAT64 as specified in this document supports both Endpoint-Independent Filtering and Address-Dependent Filtering, both for TCPand UDP as well as filtering of ICMP packets.If a NAT64 performs Endpoint-Independent Filtering of incoming IPv4packets, then an incoming IPv4 packet is dropped unless the NAT64 has state for the destination transport address of the incoming IPv4packet.If a NAT64 performs Address-Dependent Filtering of incoming IPv4packets, then an incoming IPv4 packet is dropped unless the NAT64 has state involving the destination transport address of the IPv4incoming packet and the particular source IP address of the incoming IPv4 packet.2. TerminologyThis section provides a definitive reference for all the terms usedin this document.The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT","SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].The following additional terms are used in this document:3-Tuple: The tuple (source IP address, destination IP address, ICMP Identifier). A 3-tuple uniquely identifies an ICMP Query session. When an ICMP Query session flows through a NAT64, each session has two different 3-tuples: one with IPv4 addresses and one with IPv6 addresses.5-Tuple: The tuple (source IP address, source port, destination IPaddress, destination port, transport protocol). A 5-tupleuniquely identifies a UDP/TCP session. When a UDP/TCP sessionflows through a NAT64, each session has two different 5-tuples:one with IPv4 addresses and one with IPv6 addresses.Bagnulo, et al. Standards Track [Page 11]BIB: Binding Information Base. A table of bindings kept by a NAT64. Each NAT64 has a BIB for each translated protocol. Animplementation compliant to this document would have a BIB forTCP, one for UDP, and one for ICMP Queries. Additional BIBs would be added to support other protocols, such as SCTP.Endpoint-Independent Mapping: In NAT64, using the same mapping forall the sessions involving a given IPv6 transport address of anIPv6 host (irrespectively of the transport address of the IPv4host involved in the communication). Endpoint-Independent Mapping is important for peer-to-peer communication. See [RFC4787] forthe definition of the different types of mappings in IPv4-to-IPv4 NATs.Filtering, Endpoint-Independent: The NAT64 only filters incomingIPv4 packets destined to a transport address for which there is no state in the NAT64, regardless of the source IPv4 transportaddress. The NAT forwards any packets destined to any transportaddress for which it has state. In other words, having state for a given transport address is sufficient to allow any packets back to the internal endpoint. See [RFC4787] for the definition of the different types of filtering in IPv4-to-IPv4 NATs.Filtering, Address-Dependent: The NAT64 filters incoming IPv4packets destined to a transport address for which there is nostate (similar to the Endpoint-Independent Filtering).Additionally, the NAT64 will filter out incoming IPv4 packetscoming from a given IPv4 address X and destined for a transportaddress for which it has state if the NAT64 has not sent packetsto X previously (independently of the port used by X). In otherwords, for receiving packets from a specific IPv4 endpoint, it is necessary for the IPv6 endpoint to send packets first to thatspecific IPv4 endpoint’s IP address.Hairpinning: Having a packet do a "U-turn" inside a NAT and comeback out the same side as it arrived on. If the destination IPv6 address and its embedded IPv4 address are both assigned to theNAT64 itself, then the packet is being sent to another IPv6 hostconnected to the same NAT64. Such a packet is called a ’hairpinpacket’. A NAT64 that forwards hairpin packets back to the IPv6host is defined as supporting "hairpinning". Hairpinning support is important for peer-to-peer applications, as there are caseswhen two different hosts on the same side of a NAT can onlycommunicate using sessions that hairpin through the NAT. Hairpin packets can be either TCP or UDP. More detailed explanation ofhairpinning and examples for the UDP case can be found in[RFC4787].Bagnulo, et al. Standards Track [Page 12]ICMP Query packet: ICMP packets that are not ICMP error messages.For ICMPv6, ICMPv6 Query Messages are the ICMPv6 Informationalmessages as defined in [RFC4443]. For ICMPv4, ICMPv4 Querymessages are all ICMPv4 messages that are not ICMPv4 errormessages.Mapping or Binding: A mapping between an IPv6 transport address and a IPv4 transport address or a mapping between an (IPv6 address,ICMPv6 Identifier) pair and an (IPv4 address, ICMPv4 Identifier)pair. Used to translate the addresses and ports / ICMPIdentifiers of packets flowing between the IPv6 host and the IPv4 host. In NAT64, the IPv4 address and port / ICMPv4 Identifier is always one assigned to the NAT64 itself, while the IPv6 addressand port / ICMPv6 Identifier belongs to some IPv6 host.Session: The flow of packets between two different hosts. This may be TCP, UDP, or ICMP Queries. In NAT64, typically one host is an IPv4 host, and the other one is an IPv6 host. However, due tohairpinning, both hosts might be IPv6 hosts.Session table: A table of sessions kept by a NAT64. Each NAT64 has three session tables, one for TCP, one for UDP, and one for ICMPQueries.Stateful NAT64: A function that has per-flow state that translatesIPv6 packets to IPv4 packets and vice versa, for TCP, UDP, andICMP. The NAT64 uses binding state to perform the translationbetween IPv6 and IPv4 addresses. In this document, we also refer to stateful NAT64 simply as NAT64.Stateful NAT64 device: The device where the NAT64 function isexecuted. In this document, we also refer to stateful NAT64device simply as NAT64 device.Transport Address: The combination of an IPv6 or IPv4 address and a port. Typically written as (IP address,port), e.g.,(192.0.2.15,8001).Tuple: Refers to either a 3-tuple or a 5-tuple as defined above.For a detailed understanding of this document, the reader should also be familiar with NAT terminology [RFC4787].Bagnulo, et al. Standards Track [Page 13]。
重点中学小升初分班考试英语试题及答案
重点中学小升初分班考试英语试题一、根据句意，将所缺单词补充完整，首字母已给出。
1.----Be quiet please .The boy is s___________ .----Oh，sorry . We won‘t shout from now on .2. ----What date is it today？----It’s the s_______of August .We can enjoy Olympics in six days .3 .----Look！ I have a new skirt today .----How cute you look！Your skirt is more beautiful than m__________ .4 .----What do you know about Yao Ming？----He is one of the tallest basketball p_________in the world .5 .----I can‘t learn English well .----You don’t read enough . You should do m_________ reading .6 .----Was he born in S___________？----Yes . It‘s the ninth month of the year . And he likes autumn a lot .7 .----Sue’s father is a policeman .How a ____________her mother ？----She is a nurse .She works in that hospital .8 .----Tom is so glad today .He is talking with others h__________all the time .----He must have something great . Let‘s go and ask about it .9 .----What are you going to do this Sunday？----I am going s________with my friends .It must be fun to walk in shopping malls .10 .----I am very t_________ . I can’t walk any more .----Let me help you .二、选择填空：1.More than ________VIPs will come to Beijing for the Olympic Games .A .eight hundredsB .eight hundredC .eight hundred ofD . eight hundreds of2.I can see Eddie _________his computer _______the window .A . at； onB . on； atC . at； throughD . on； by3.My bike is not here .Will you _________yours _________me ？A . borrow； toB . borrow； fromC .lend； fromD . lend； to4.Do you know___________？A . who he isB . who is heC . what he likeD . what does he like5. There are about six bridges over Yangtze River in Jiangsu . One is for trains，__________are all for cars and tricks .A . the otherB . the othersC . another fiveD . Others6. ---- I am very sorry but I can‘t help you now .----_________.A . That’s rightB . You‘re welcomeC . Thank you all the sameD . How sorry I am .7._______weather we are having these days ！A . What a badB . How nice aC . How niceD . What bad8.Mr Green is a new teacher at our school .His job is __________ .A .teach our EnglishB .teaching us EnglishC .teach us EnglishD .to teach our English9.Stop ________ .The teacher is coming for the new class .A . talkB . to talkC . talkingD . Talks10.I didn’t think she had _______more CDs __________Mike .A . so； asB . much； thanC . as； asD . many； than11.We all like him because he says __________but does much .far A . little B . a little C . much D . Many12. _______ is the most interesting of _________ .A . Unit Three ； Book ThreeB . The Unit Three ； the Book ThreeC . Third Unit ； Third BookD . The Third Unit ； the Three Book三、用所给动词的适当形式填空：1. Jim is good at P .E . He gets up early and __________ (do) some sports every morning .2. ----_________ Timmy __________ (visit) his friends next ？ ----Yes ， he is. Sunday3. Millie __________ (go) the park by herself and had a good time there .4. The workers at the repair shop say our car needs ___________ (mend) .5. I have no homework this afternoon . How about _________ (fly) kites in the park ？6. Many students are in the room now. They (watch) Kungfu Panda on TV. ___________四、完形填空：Do you like to shop on the Internet ？ Things online are very cheap . I often get ____ 1____ online . Let me tell you how to buy one when i want to know something about a book. Firstly ， I write an e-mail to the online shop. Then they will ____2___ me some pictures of the book . I think this is very helpful .Online shops are _____3____ open. I can do shopping even at midnight if I want to . Real shops usually close _____4_____ nine o ‘clock in the evening .After you ____5___ the online shopkeeper what you want ， you can have your things in a few days. When you go shopping in a shopping ， you have to talk ____6____ with the mallI am teaching my grandmother ___8___ online. She cannot walk very (远) . ___9____ it is easy for her to shop online . My brother wants to learn how to do it too . He is very _____ 10____ most of the time . When he has a little free time ， he can shop online . So you see ， shopping online saves time .1. A . shoes B . books C . food D . toys2. A . tell B . show C . give D . sellshopkeeper and walk a lot . I don ’t like it ， because i get tired _____7____ .3. A . sometimes B . often C . always D . usually4. A . in B . on C . at D . for5. A . spend B . pay C . cost D . buy6. A . a lot of B . much C . lots of D . many7. A . easy B . easily C . happy D . happily8. A . why to shop B . where to shop C . how to shop D . when to shop9. A . because B . for C . so D . but10. A . healthy B . free C .lazy D . busy五、根据中文意思完成下列句子，每空一词：1. 这个图标的意思是“不要喧哗”。
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Linux 2.4 NAT HOWTO 简体中文版Rusty Russell, mailing list netfilter@$Revision: 1.3 $ $Date: 2002/06/05 13:21:56 $简体中文：洋鬼鬼·NetSnake感谢网中人netmanforever@ 提供的繁体参照此文档说明如何进行伪装、透明代理、端口转发，和基于Linux 2.4内核其他类型的网络地址转换(Network Address Translations)。
1. 简介2. 官方站点及列表2.1 什么是NAT？2.2 我为什么需要NAT？3. NAT的两种类型4. 从2.0和2.2内核的快速转换4.1 我只想伪装！救命！4.2 关于ipmasqadm5. NAT可以控制什么5.1 用iptables做简单的选择5.2 关于应当挑选哪些包来拆分（mangle）的要点6. 说说如何拆分包吧6.1 源地址NAT6.1.1 伪装6.2 目的地址NAT6.2.1 重定向6.3 深层次的映射6.3.1 一个范围内多地址的选择6.3.2 建立空的NAT映射6.3.3 标准NAT行为6.3.4 内部源端口映射6.3.5 如果NAT失败会怎样？6.3.6 多重映射，重叠和冲突6.3.7 修改本地生成的连接的目标地址7. 特定的协议8. 关于NAT的警告9. 源地址NAT和选路10. 同一网络内的目标地址NAT11. 感谢1. 简介欢迎，亲爱的读者。
你将要深入迷人的（有时是令人厌烦的）NAT世界：网络地址转换，这篇HOWTO可以成为你的Linux2.4内核及其以后的准确指南。
在Linux2.4（内核版本），引入了一个叫“netfilter”的部分，专门用于拆分（mangling）（IP）包的。
他上一层提供NAT，是完全依靠以前的内核制作的。
（译者注：mangle实在找不出什么合适的翻译，抱歉）(C) 2000 Paul `Rusty' Russell. Licensed under the GNU GPL.2、官方站点及列表位置这里有三个官方站点：o Thanks to Filewatcher .o Thanks to The Samba Team and SGI .o Thanks to Harald Welte .你可以通过以下站点访问全部相关站点。
and 以下是netfilter官方邮件列表/contact.html#list.2、1 什么是网络地址转换（Network Address Translation）？通常，，网络中的（IP）包从他们的源（地址）出发（比如你家的电脑），到他们的目的地（比如），会经过很多不同的连接（links）：例如我所在澳大利亚就有19个。
这些连接不会真去修改你的包：他们只是照原样传出去。
（译者注：这里的links应当认为是所有网络节点，包括主机、路由器等。
通常，路由器并不是原样传送包，它至少会修改其中一点：TTL）如果这些连接有一个做NAT，那么它（们）就会修改通过它们的包的源或者目标（地址）。
正如你猜象的那样，这并非系统设计成那样的，而是NAT做了一些事情。
通常进行NAT的连接（主机、服务器、路由器）会记住它是如何拆分包的，而当另一头响应的包通过时，它会对响应的包做相反的拆分，所以世界仍在运转。
（译者注：这一段的mangle应该想象为修改更合适）2、2 我为什么要NAT？在完美的世界里，你不需要。
同时，主要的理由是：用调制解调器连接Internet在你拨号上网时，大部分ISP只会给你一个IP地址，你可以发送你想发送的任何源地址包，但是只有响应这个（ISP给你的）地址的包才会返回。
如果这种情况下你想有多台不同的机器上网（比如一个家庭网络），你就需要NAT。
这是现在NAT用得最多的功能，Linux世界的"masquerading"（伪装）非常出名，我称之为SNAT（SNAT即Source NAT，源地址转换），因为你改变了第一个包的源地址。
（译者：关于IP数据报的第一个包等内容，请参见各TCP/IP书籍）多（重）服务器有时你想改变进入网络中的包的目标地址（路由）。
经常的，这是因为（就像上面的例子），你只有一个IP地址，但是你希望大家可以通过到那个“真实”的IP地址进入内部。
如果你重写了进入包的目标地址，这样就没问题了。
这种NAT在以前的Linux版本中被称为端口转发。
一个常见的变种是负载均衡，在一组机器上做映射。
如果你要进行严格的比例限制，可能需要参考Linux Virtual Server。
透明代理有时你可能想要经过你的Linux的包被送往本机的一个程序。
这就需要用到透明代理了：代理是位于你的网络和外部世界之间的一个程序，帮助二者进行通信。
之所以称为透明，是你的网络根本不知道他在和代理交谈，当然直到代理没有正常工作。
Squid可以配置为干这项工作，在以前Linux版本中它被称作重定向或者透明代理。
3、NAT的两种类型我把NAT分为两种不同的类型：源NAT(SNAT)和目标NAT(DNAT)。
（译者注：以下不再翻译SNAT和DNAT，直接用Source NAT和Destination NAT）Source NAT是指修改第一个包的源地址：也就是说，改变连接的来源地。
Source NAT会在包送出之前的最后一刻做好post-routing（动作），伪装是SNAT的一种特殊形式。
Destination NAT 是指修改第一个包的目标地址：也就是说，改变连接的目的地。
Destination NAT 总是在包进入以后（马上）进行before routing（动作）。
端口转发、负载均衡和透明代理都属于DNAT。
4、从2.0和2.2内核的快速转换如果你还在为从2.0（ipfwadm）到2.2（ipchains）的转换手忙脚乱的话，很抱歉。
不过这也算是个喜忧半参的消息。
首先，你可以轻松的使用ipchains和ipfwadm，就像从前一样。
不过你需要安装最新发布的netfilter中的“ipchains.o”或者“ipfwadm.o”内核模块。
它们是互斥的（你会被警告），而且不能和任何其他netfilter模块结合。
一旦这其中某个模块被载入，你可以像以前一样使用ipchains和ipfwadm，不过仍有以下区别：用ipchains -M -S，或者用ipfwadm -M -s设置伪装超时不再有效。
因为超时已经转移到新的NAT构架中，所以这不能做任何事。
在详细的伪装列表中，init_seq、delta和previous_delat字段始终为零。
归零和列表计数器的-Z -L不再有效：计数器不能被归零。
这类向后兼容的部分可能和大部分连接都不能有效配合：不要在你的公司网关中使用开发者们还要注意：无论是否使用伪装，现在可以绑定61000 - 65095之间的端口。
以前的伪装代码占用了这部分端口，因此不能使用。
尚未成文的“getsockname”，透明代理程序可以用来发现那些已不再工作的连接的真实目的地址。
尚未成文的“bind-to-foreign-address”同样还未启用：这个用于完整透明代理的设想。
4、1 我只想伪装！救命！这是绝大部分人想要的。
如果你用PPP拨号上网来动态得到IP （如果你不知道，那应该就是的）你可能只想告诉你的机器，所有来自内部网络的包，要看上去同PPP连接服务器上的包一样。
# 装载NAT模块（这取代了其他的）modprobe iptable_nat# 在NAT表中(-t nat)，路由后POSTROUTING 加入一条规则(-A)# 所有由ppp0送出的包(-o ppp0) 会被伪装( -j MASQUERADE)。
iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE# 开启IP转发echo 1 > /proc/sys/net/ipv4/ip_forward注意这时你没有做任何的包过滤：如果需要，参见the Packet Filtering HOWTO。
4、2 那么ip masqadm呢？这个完全取决于用户，所以我不担心向后兼容的问题。
你可以简单的使用“iptables -t nat”做端口转发。
例如，在Linux2.2你要做：# 在2.2内核，把指向1.2.3.4 8080端口的TCP包转到192.168.1.1的80端口ipmasqadm portfw -a -P tcp -L 1.2.3.4 8080 -R 192.168.1.1 80现在你可以这样：# 2.4内核，在NAT（-t nat）表中加入一条规则，在路由之前（-A PREROUTING）指向# 1.2.3.4（-d 1.2.3.4）8080端口（--dport 8080）的TCP包（-p tcp）目标地址（-j DNAT）# 被重定向到192.168.1.1的80端口（--to 192.168.1.1:80）。
iptables -A PREROUTING -t nat -p tcp -d 1.2.3.4 --dport 8080 -j DNAT --to 192.168.1.1:805、NAT可以控制什么你需要创建NAT规则，以告诉内核哪些连接将被改变和如何改变。
要做到这一点，我们要用到一个用处很多的iptables 工具，并告诉它用指定的“-t nat”选项修改NAT表。
NAT规则表包含三个称为“链”的列表：每个规则都按顺序检查包，直到有一个匹配。
其中两个被称为PREROUTING（用于Destination NAT，当包进入时检查），POSTROUTING（用于Source NAT，包离开时检查），第三个叫OUTPUT，这里可以忽略。
如果我有足够的艺术天分的话，下面的见图会准确的说明上述概念：_____ _____/ \ / \PREROUTING -->[Routing ]----------------->POSTROUTING----->\D-NAT/ [Decision] \S-NAT/| ^| || || || || || |--------> Local Process ------上述每一点，当我们查看连接（中）的包时，如果是一个新的连接，我们查看NAT表中相对应的链，看看需要做些什么。
其结果就会作为对这个连接后面所有包的反应。
（译者注：此处的连接是指一个HTTP会话之类的连接，而非物理上的线路、节点）5、1 用iptables做简单的选择下面列出了iptables的一些标准选项。
所有双横杠（--）的选项都是可以缩写的。