2021中考-选择填空满分限时训练7
2021年中考英语选词填空专项训练
选词填空专项训练We can’t stop an earthquake(地震)；but we can do things to make sure they don’t destroy(毁坏) whole cities. First；it is not a 1 .________ idea to build houses along lines where 2. ________ of the earth’s plates(板块) join together. Second；if you think there 3. ________ be an earthquake；it is better to build houses on rocks ；not on 4. ________. Third；you must make the houses as 5. ________ as possible. Weak buildings will fall down in an earthquake；but strong ones may 6. ________ ..Scientists are 7. ________ that one day an even bigger earthquake will hit the part around San Francisco(旧金山) . They call it “ The Big One ”. However；people today are still building more 8. ________. The population in and around San Francisco is 9. ________ ten times more than it was in 1906. This means that 10. ________ there is another earthquake；a great many houses and buildings will be destroyed.broken umbrellas；and then he took them to a big shop in London. They were 2 ________ there.One day Mr. Brown went to London by train. He 3 ________ to take an umbrella with him that day. Sitting in front of him was a man with an umbrella standing 4 _______ the seat. When the train arrived in London；Mr. Brown 5 ________ up the umbrella as he often did during his journey by train. Just as he was getting off；he was 6 ________ by the man. He said angrily；“That’s 7________ !” Mr. Brown’ s face turned red and he gave it back to the man at once.When Mr Brown got to the big shop；the shopkeeper had got his six umbrellas ready. After a good look at 8 ________ of them；he said；“You’ve mended them very well.”In the afternoon he got into the train again. The 9 ________ man was in the same seat. He looked at Mr Brown and his six umbrellas；“You’ve had a 10 ________ day；” he said.A farmer saw an old man growing something on the other side of the river.The farmer 1. ________ out to him；“ What are you growing ；Grandpa? ”The old man 2 . ________ for a moment；then said；“Swim over 3. ________ I’ll tell you.”The farmer didn’t like the 4. ________ of swimming across the river. But he wanted to know 5. ________ the old man was doing. He swam over. The old man said very 6. ________ in his ear；“ I’m planting peas in my 7. ________ .”“ You should have shouted. I would have 8. ________ quite clearly on that side.” Said the farmer.“ Oh；no；I wouldn’t 9. ________ that . The sparrows would have heard me and 10. ________ my peas.”Mrs Andrews had a young cat；and it was the cat’s first winter. One evening it was 1.________ when it began to snow heavily. Mrs Andrews looked 2. ________it everywhere and shouted its name；but she did not find it；3. ________ she telephone the police and said；“ I have4. ________ a small black cat. Has5. ________ found one? ”“ No；madam；” said the policeman at the other end；“ But cats are really very 6. ________ animals. They sometimes live for days in the snow；and when it melts (融化) or somebody finds them；they are quite 7. ________ .”Mrs Andrews felt 8. ________ when she heard this. “ And ；” she said；“ Our cat is very 9. ________. She almost talks. ”The policeman was getting tired；“Well then；” he said “ Why don’t you put yourHere are some old ways to sending messages.An Egyptian(埃及人) put his ear to the ground. He 1 . ________ the horses coming this way. He ran to 2. ________ his people . He was a 3. ________ . That was one way for Egyptians to send messages.People in 4.________ countries sent message；too. When enemies came；one man beat his drum. In the next village people heard the drum and beat their drums；too. The messages went from village to village by 5.________ .Much 6. ________ ；some armies (军队) kept many pigeons(鸽子) . These pigeons always 7. ________ back. When a soldier was sent far away from his own 8. ________ ；he might take a pigeon along. He could tie a message to the bird’s leg. It would fly back 9. ________ the soldier’s message.These are shown ways to send messages. Can you think of more 10. ________?2. ________ one second；light travels about 300；000 kilometers；but sound travels only 340 meters. You can get some idea of this difference by3. ________ the start of a running match. If you stand far away from the starter(发令员)；you can see smoke4.________ from his gun5.________ the sound reaches your ears.The fast speed of light produces some strange facts. The nearest star is 6. ________ far awaythat light which you can see from it tonight started to travel to you four years 7. ________ at a speed of nearly two million kilometers every minute. The light from some of tonight’s started on 8. ________ journey towards you even before you were born.So；if we want to be honest(诚实)；we 9. ________ say ；“The stars are shining brightly tonight.”We have to say；“ The stars look nice. They were 10. ________ four years ago but their light has just reached our earth. ”“I like football；Doctor.” He said；“ Please help me. My life has 2. ________ been a good one since I became 3. ________ in football and it is getting worse and worse. I can’t even 4.________ from it in my sleep. When I close my 5.________；I’m out there in the football field and 6. ________ after a flying ball. When I wake up；I’m more 7. ________than I was before I went to bed. What am I going to do? ”The doctor sat back and said；“First of all；you 8. ________ to do your best not to dream(做梦) about football. Before you fall asleep；try to 9. ________about something else. Try to think that you are at a party and someone is going to give you several million dollars.”“ Are you crazy (疯了) ?”the man shouted；“ I’ll 10. ________ the ball !”You may think there is nothing but sand in the desert of the world；but it is not true. In the desert we can 1._______ stones. We can see hills；too. There is a little rain in the 2.________；but it is not 3. ______ for most plants.The animals are 4. _______ to the desert people in many ways. The desert people eat the meat and drink the milk of the animals. They use their skins to 5. ________ shoes；water bags and even tents(帐篷). They use the camels(骆驼) for 6. _______ things.The people of the desert have to keep 7. _______ from places to place. They must always look for grass or desert plants for their animals. They usually live in the tents. When there is mo more food for their animals；they take down their tents；put them on the camels and move to 8. _______ place. The desert people are very 9. _______. No man in the desert would ever refuse to help the people in 10._______ and give them food and water.The world of the out-of doors is full of secrets. And 1. ________ are so interesting that quite a lot of people are busy studying them. All around us are birds；animals；trees and flowers. The facts about 2.________ they live and grow are as interesting as anything could be.Do you know that one of the great presidents of the United States 3 ________ hours andhours studying birds? A businessman who lives near New York City became so interested in insects(昆虫) that he began to collect them. He now has more than one thousand different kinds 4. ________ kept in the glass boxes.Come then with me；and I will help you find some of Nature’s secrets. Let us go quietly through the woods and fields. Here we shall find how a rabbit tells the other rabbits that there is danger. We shall follow a mother bear and her young ones as they search for food and get ready for 5. ________ sleep. We shall watch bees 6. ________ in the air to let other bees know where they can find food. I will 7.________ you many other interesting things；but the 8. ________ thing that I can teach you is to keep your eyes and ears 9.________ when you go out of doors. Nature tells her secrets 10.________ to people who look and listen carefully.Usually he wears a beard(蓄着胡须). Since it has been 2.________ there；he has taken it off (剃掉). But his passport photo shows him with his 3. ________.An officer looks at the 4. ________for a moment；and says；"Will you excuse me? Please sit down. I shan't keep you long." With this；he walks away；shows the photo to a second 5.________；and says: "I know that face." The second officer looks at the 6. ________ and asks where Mr Hill has come from. When he hears that Mr Hill has arrived back from Paris；the 7.________officer smiles and says: "An Englishman with a beard stole a painting in Paris on Friday；And that man looks just the kind of man..."8.________ it comes to the first officer who Mr Hill is. He returns to him；and asks: "Did you9. ________ at the No.2. High School?" When Mr Hill answers；10. ________；that he did；the first officer smiles and says: "I thought so. I'm Jack Smith. You taught me French. You haven't changed a bit."Thomas Edison was a great American 1.________ . When he was a child；he was always 2.________ questions and trying out new ideas. No matter 3.________ hard it was；he never gave up.Young Tom was in school for only three months. His teacher didn’t understand why he had 4.________ many strange questions. Most of them were not about his lessons. The teacher didn’t want to teach Tom any 5.________ . He asked Tom’s mother to take the boy home. Tom’s mother taught him to read and write；and she found him 6.________ a very good pupil. He learnt very fast and became very 7.________ in science.One day ；he saw a little boy 8.________ on the railway tracks at a station. A train was coming near quiclly；and the boy was too frightened to move. Edison rushed out and carried the boy to 9 .________. The boy’s father was so 10.________ that he taught Edison to send messages by telegraph.( 12 )"Dreams (梦) may be more important than sleep. We all need to dream；" some scientists say.Dreams take up about one quarter of our 1 .________ time. People have several2. ________each night. Dreams are like short films. They are usually in colour. Some dreams are3.________old films. They come to us over and over4.________. That may be because the dreamer is worrying about something. Dreaming may be a way of trying to find an answer.Some people get new ideas5. ________ their work from dreams. They may have been 6.________ about their work all day. These thoughts can carry over into dreams.Sometimes we 7. ________with a good feeling from a dream. But often we can't remember the dream. Dreams can disappear (消失) 8. ________ from memory (记忆).Too much dreaming can be harmful (有害的). The 9. ________ we sleep；the longer we dream. The mind is hard at work when we dream. That is 10. ________ we may have a long sleep and still wake up tired.More than seven hundred years ago；the Prince of Wales had a very big and brave dog called Gelert.One day the Prince wanted to go 1. ________ with his men. He told his 2. ________ to stay at home and look after his baby son. The baby was in a wooden cradle (摇篮)；which was like a small bed.When the Prince came back from hunting；Gelert ran out to meet his master. He wagged his tail and jumped up to put his paws （前爪）on the Prince's chest. Then the Prince saw the blood on Gelert's jaws and head."What have you done?" the Prince said. He rushed into his house and 3. ________his baby son. The cradle was lying on its side on the floor. The clothes were torn and there was blood on them."So you have killed my son?" the Prince said angrily. "You unfaithful dog!" He took out his sword（剑）and 4. ________ the dog. Just as Gelert was 5. ________；he managed to bark. Then the Prince heard a baby call to the dog.The Prince ran out of the house and saw his son lying on the ground unhurt. Near him was a dead6. ________. Then the Prince knew that Gelert had defended（保卫）the baby and killed thewolf.The Prince ran7.________ into the house but he was too late. Gelert was dead. The Prince was very sad indeed. 8. ________ran down his face when he realized 'he had killed 9. ________faithful friend. The Prince carried the body of his brave dog to the top of a mountain and buried him there. After this；the Prince never smiled again. Every morning at dawn；he walked up the mountain and stood by the dog's grave for a few minutes.If you go to Mount Snowdon in Wales；people will show you where Gelert is buried. There is a sign by his grave. It10.________people of a brave and faithful dog.Satellites Forecast the WeatherNow satellites are helping to forecast (预报) the weather. They are in space；and they can reach any part of the world. The 1.________ take pictures of the atmosphere (大气)；because this is where the weather forms (形成). They send these pictures to the 2. ________ station. So the scientists there can see the weather of any part of the world and tell how the weather will change.Today；nearly five hundred weather stations in sixty countries can 3. ________ satellite pictures. 4. ________they receive the new pictures；they compare (比较) them with the earlier ones. Perhaps they may find that the clouds have 5. ________during the last few hours. This may mean that the weather on the ground may soon change；too. In their next weather 6. ________；they can tell people about it. So the weather satellites are of a great7. ________to the scientists at the station. In the past they could forecast the weather for about 24 or 48 hours 8. ________. Now they can make good forecasts for three 9 ________ five days. Soon；perhaps；they may be able to forecast the weather 10. ________ a week or more ahead.Catherine was a famous writer of children's stories. She lived in a fine old house in a small town near London. Often she worked at home；in her quiet 1.________.Long before her books became popular；she had tried to teach 2 how to use a computer. And now she typed （打字）all her stories on her computer. But sometimes she had to 3 the house to get some books from the library or have a meeting. She didn't like being away because she was worried about burglar（盗贼）.So she was very careful. Just before leaving；she always put a full cup of coffee on the writing desk；and left the radio playing to make a burglar think someone 4 be at home.One day she came back after a day out；and found that there was something different in her house. There was only a little 5. lift in the cup；and the radio was off. But when she looked at her computer；she saw it was 6. ；and someone had typed in a new story. She had no idea who had got in；or how；because none of the doors or windows was broken. Then she sat down to read the story. To her surprise；it was a very good one. "I'll use it in my 7. book!" she said 8 .The next month she had to go to London. She put a cup of coffee and a plate of sandwiches on the desk. When she returned；the coffee and the sandwiches had 9. .She ran to the computer. This time there was only a 10. on the screen（屏幕）."IT'S NOT YOUR STORY.IT'S MINE!" it said.Tom lived a way from town. One day he went into town to buy something in the shop；and after he bought 1. ________ he wanted；he went into a restaurant and sat 2 . ________ at the table. When he looked round；he saw some old people 3. ________ eyeglasses on before 4. ________ their books；so after lunch he went to a shop to buy 5. ________；too. He walked along the road；and soon found a 6. ________.The man in the shop made him 7. ________on a lot of glasses；but each time Tom said；“ No；I can’t read with these. ”The man became 8 . ________and more puzzled (困惑) . At last he said；“ Excuse me；but 9. ________you read at all?”“ No；I can’t! ” Tom said；“10. ________ I can read；do you think I will come here to buy glasses? ”In my spare time；I paint designs on T-shirts. I got the idea two years 1 for my 2 birthday present. The shop wanted $ 20 for a special design 3 a T-shirt；so I decided to do it 4 . I bought a white cotton T-shirt 5 $6 and some paints；and I painted a lion on the front. My brother loved it!Painting T-shirts is great fun. You 6 be a great artist；you can just paint shapes and lines. The T-shirts are the 7 expensive part of my hobby. Also you have to use special fabric paints and you need to buy good quality brushes.I love my hobby 8 I can make T-shirts that no-one else has. I give a lot of them away 9 presents to my family and friends. Sometimes；I sell them. Since I started；I’ve 10 about 60 T-shirts and each one is different.A: Good morning；madam. May I help you?B: Yes；I’m afraid I 1 my handbag on the taxi this morning!A: What’s 2 the handbag?B: About 5000 yuan.A: 3 else?B: Yes；my ID card；I think.A: By the way；have you 4 for the taxi ticket?B: Yes；the ticket 5 is 3456789.A: Well；I’ll help you to call the taxi 6 . ( Knocking at the door)B: Come in；please.A: Good morning；sir. I found this handbag on my taxi and I 7 it here. There’s much money 8 .B: Thank you very much. (turning to the woman). Is this your handbag?A: Yes；it’s 9 . Thank goodness! 10 a kind man! Thank you.Have you ever been to Disneyland? For most of the kids 1 the world；this 2 park is a fantastic place for them to have fun. When we 3 young；we all have heard 4 Mickey Mouse；Sleeping beauty；Snow White and many Disney characters. Some of us 5 have seen them in cartoons. Actually；you can go to see them all in a theme park. Now；there are four 6 Disneyland amusement parks all over the world. Two are in the United States；one is in Tokyo；and the 7 is in France. There are not only some amusement attractions there ；8 also many specials withDisney characters. In Disneyland；you can have a lot of fun watching Disney movies；9 in Disney restaurants；and buying Disney 10 .1 the passageeasy to keep fit.1)Eat all kinds of foods；especially fruits and vegetables.You may have a favourite kind of food；but the best 2 is to eat as many kinds as possible. If you eat 3 foods；you’re more likely to get the nutrients your body needs . Taste new foods that you 4 tried before. Some foods；such as green vegetables；are very important. Have five servings(份) of fruits and three vegetables.2)Drink water and milk often.When you are really 5 ；cold water is the No. 1 choice. Kids need calcium(钙) to grow strong；and milk is a great source of this mineral (矿物质) . How much do children 6 ? About three glasses of milk every day.3) Limit screen time.What’s screen time? It’s the 7 for watching TV；DVDs；and videos；8 computer games；and using the computer. If you spend much time 9 these activities；you may have less time left to take 10 ；such as playing basketball；bicycling；and swimming.1A good place to camp for the whole night. We make a campfire so that we can cook our2 . We roasted some hot dogs and potatoes and3 some lemonade. Whenit got 4 ；we told ghost stories by sitting 5 the campfire.Later when we lay down to go to 6 ；we listened to the sounds of crickets(蟋蟀) and some 7 moving around in the grass. We 8 there were some ghosts nearby. “ What?” we asked. “ I think I hear someone walking in the woods. ” Kathy said. Soon we all 9 footsteps and we were all so 10 that we couldn’t go to sleep.Of course；there was no one there；but we have very active imagination(想象).A: What are you going to do next weekend?B: I have no 1 . What about you?A: I don’t know. Do you want to do something 2 me?B: Sure. What do you want to do?A: How about 3 fishing on Saturday?B: OK. 4 are we going to meet?A: Let’s meet at my house. My father has a boat. He can 5 us fishing on the lake. B: What time shall we leave?A: Let’s leave at 5: 30 in the 6 . Fishing is good at that time.B: So early? Can we 7 it a little later?A: Well；no 8 . What about 6:00?B: Great. We are sure to 9 ourselves. 10 you at 6:00 on Saturday morning.A: OK. Bye!。
2021年内蒙古中考英语重点题型限时训练： 完形填空+ 阅读理解(A)+ 选词填空+ 任务型阅读
完形填空+ 阅读理解(A)+ 选词填空+ 任务型阅读Ⅰ.完形填空He has millions of students from all over the world. They listen to his classes online. They 1see his face on the screen. Salman Khan, 42, from the US, is the founder(创始人) of the learning website Khan Academy.Unlike other online courses that film teachers 2classes, Khan’s videos only use his voice and a digital blackboard for writing. He says he doesn’t want a human face to distract(使分心) students. Khan also makes his classes 310 to 15 minutes so that students won’t lose interest. They can also get scores from taking classes.The courses are translated into more than 36 different languages 4Chinese. About 80 teachers from the world’s top universities are now also teaching on the website. But all this started nine years ago with just one man—Khan. These kinds of special courses make Khan Academy one of the world’s 5online education websites.In 2006, Khan made homemade videos to help his 6grade cousin with math. He posted the videos online and got thousands of views. This encouraged him to make more videos and create his own website Khan Academy.Khan understands that many kids, especially those in developing countries, cannot get a good education. He has three degrees from universities. He wants to use his 7to help more people. Thus, his courses are all offered for free. “Our task is to 8 a free, world-class education for anyone, anywhere,” he said.Khan’s website has 9become very popular worldwide but won a lot of respect(尊重). Even Bill Gates, the founder of Microsoft, is one of his fans. Gates 10over $1.5 million to support Khan and named him “the teacher to the world”.()1.A.always uallyC.neverD.sometimes()2.A.to give B.givingC.giveD.gave()3.A.as long as B.as much asC.as short asD.as soon as()4.A.including B.withC.asD.beside()5.A.least popular B.more popularC.popularD.most popular()6.A.nine B.ninethC.ninthD.the ninth()7.A.knowledge B.fameC.courageD.value()8.A.give B.offerC.provideD.pay()9.A.ever B.alreadyC.notD.not only()10.A.gave out B.gave offC.gave upD.gave awayⅠ. 阅读理解The Digital Media Summer CampThe digital media(数字媒体) summer camp is a great chance for students aged 7 to 18 to have STEM courses. Students can learn to build an app, program a robot, or explore (探索) the world of music production. STEM courses will also help students create, learn teamwork and solve problems.Students will learn from our teachers who have been employed(聘用) for both their teaching experience and rich knowledge in their fields. Besides making new friends, students will leave with amazing final projects and lasting memories.Time: August 1st—August 31st Daily Schedule:8:30 a.m.—10:00 a.m. 10:30 a.m.—12:00 p.m. 12:00 p.m.—1:30 p.m. 1:30 p.m.—3:00 p.m. 3:30 p.m.—4:30 p.m.Hands-on STEM Instruction Continued Instruction & CreationLunch BreakRobots ProgrammingMusic Appreciation(鉴赏)Saturday Open House:At 3:30 p.m. every Saturday, parents are invited to our Open House. Students can show the projects they have been working on. Their parents can meet the teachers and explore more chances for their children to continue learning and creating.1.The digital media summer camp can help students .()A.keep healthyB.learn a foreign languageC.improve their writing abilityD.develop STEM knowledge2.Which word can best describe the teachers of the summer camp?()A.Experienced.B.Humorous.C.Young.D.Strict.3.Which of the following statements is NOT true?()A.Parents can be invited to see their kids’ projects.B.Students will leave the camp with amazing final projects.C.Students’ lunch break lasts two hours.D.Students can learn to program a robot in the summer camp.Ⅰ. 选词填空阅读下列短文,用方框内所给单词的正确形式填空。
2021年英语中考选词填空题型提升练(含答案)
2021年英语中考选词填空题型提升练Test 1根据短文内容, 从方框中选择恰当的单词完成句子, 部分单词在填入前需进行词形转换, 每个单词只能用一次, 每空只能写一词。
(2020·百色中考)Do you know that there are two special days for parents in America? One is Mother’s Day on the1. Sunday of May, and the other is Father’s Day on the third Sunday of June. On these two days, American2. often give gifts to their parents or take them out for lunch or dinner. Common gifts are flowers and cards for mothers and shirts or ties for fathers.It is becoming more and more 3. to celebrate Mother’s Day and Father’s Day in China. Chinese kids also give similar gifts to their parents. 4. , there are many ways to show our love. We don’t have to 5. a lot of money. It is also a good idea to help parents to do something instead.Test 2根据短文内容, 从方框中选择恰当的单词完成句子, 部分单词在填入前需进行词形转换, 每个单词只能用一次, 每空只能写一词。
(2018·柳州中考)There is an old saying, “Laughter is the best medicine. ” Now people are using laughter to 1.their health all around the world. In some countries special centers for treating 2. with laughter have been set up and become popular. In 2003, a study showed that laughing helped the sick get better 3.than the usual treating ways. It made them relax, and 4. was helpful for their general health. Laughing helps us feel happier. And 5. s say five minutes of laughter is as good for you as fifteen minutes in the sports hall. It also gives the body exercise.Test 3根据短文内容, 从方框中选择恰当的单词完成句子, 部分单词在填入前需进行词形转换, 每个单词只能用一次, 每空只能写一词。
(全)2021中考英语单项选择填空题解题技巧、练系及答案
中考英语单项选择填空题解题技巧、练系及答案一：解题技巧当前中考的单项选择题，纯粹考察语法和词汇的题目越来越少，主要是考察学生应用语言知识的能力。
正确的解题技巧在解题时既可以节省考试时间，又可以保证答题的准确性。
下面就中考英语单项选择题的解题技巧做一介绍：（一）注意关键词，选定正确项例1”The World Without Thieves”is a very moving film. I _______ it twice already.A. will seeB. seeC. sawD. have seen分析：本题考查现在完成时的用法；题干中的关键词twice already是常与现在完成时连用的状语，故选D2——_______________ ？——He is tall.A. How is heB. What does he likeC. What is heD. What does he look like分析从题干中关键词tall判断. 本题是考查人的外貌，所以回答得用look like，故选D（二）加强知识积累，牢记固定搭配例1His parents often encourage him _________ hard.A. workB. workingC. to workD. works分析：本题是考查动词encourage sb to do sth的固定用法，后面跟动词不定式，故选C.（三）准确把握题意，排除干扰选项。
例1After discussing，the students _________ some good ideas to work on the project. A. put upB. set upC. caught up withD. came up with分析：本题的意思：经过讨论，学生们提出了一些做这个项目的好建议。
本题考察目的是副词up与动词搭配的用法。
put up意为建造；set up意为建立；catch up with意为赶上…；这三个词组均不合题意，应予排除；而come up with意为想出，提出，刚好与题意吻合，故选D.2There ________ a football match on TV this evening.A. will haveB. is going to beC. hasD. is going to have分析：have a football match（举行足球比赛）是个固定短，需要人或者某个组织做主语，所以选项A.C.D均该排除；本题的题干是there be句型，其一般将来时的构成是there will be或there is （are）going to be.故答案选B（四）类推比较，选定答案如果对题目的备选答案没有十分把握或把握很小，不妨利用“如果A对，那么B 也对”的类推法，从而将AB予以否定。
浙江省2021年中考数学复习选择填空限时练习汇总
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通过我们的努力，能够为您解决问题，这是我们的宗旨，欢迎您下载使用!超级资源（共９套45页）浙江省2019年中考数学复习选择填空限时练习汇总选择填空限时练(一)[限时:40分钟满分:54分]一、选择题(每小题3分,共30分)1.-2的相反数是( )A. B.-2 C.2 D.-2.如图X1-1,下面几何体的俯视图是( )图X1-1图X1-23.[2018·绍兴]绿水青山就是金山银山,为了创造良好的生态生活环境,浙江省2017年清理河湖库塘淤泥约116000000方,数字116000000用科学记数法可以表示为 ( )A.1.16×109B.1.16×108C.1.16×107D.0.116×1094.把不等式组的解表示在数轴上,下列选项正确的是( )图X1-35.用反证法证明命题:在一个三角形中,至少有一个内角不大于60°.证明的第一步是( )A.假设三个内角都不大于60°B.假设三个内角都大于60°C.假设三个内角至多有一个大于60°D.假设三个内角至多有两个大于60°6.从某市8所学校中抽取共1000名学生进行800米跑达标抽样检测,结果显示该市成绩达标的学生人数超过半数,达标率达到52.5%.如图X1-4①、②反映的是本次抽样中的具体数据. 根据数据信息,下列判断:①小学高年级被抽检人数为200人;②小学、初中、高中学生中,高中生800米跑达标率最大;③小学生800米跑达标率低于33%;④高中生800米跑达标率超过70%.其中判断正确的有( )图X1-4A.0个B.1个C.2个D.3个7.如图X1-5,在▱ABCD中,用直尺和圆规作∠BAD的平分线AG交BC于点E,若BF=6,AB=5,则AE的长为( )图X1-5A.4B.6C.8D.108.已知关于x的方程ax+b=0(a≠0)的解为x=-2,点(1,3)是抛物线y=ax2+bx+c(a≠0)上的一个点,则下列四个点中一定在该抛物线上的是 ( )图X1-6A.(2,3)B.(0,3)C.(-1,3)D.(-3,3)9.如图X1-6,已知A,B是反比例函数y=(k>0,x>0)图象上的两点,BC∥x轴,交y轴于点C,动点P从坐标原点O出发,沿O→A→B→C匀速运动,终点为C,过运动路线上任意一点P作PM ⊥x轴于点M,PN⊥y轴于点N,设四边形OMPN的面积为S,P点运动的时间为t,则S关于t的函数图象大致是( )图X1-710.如图X1-8,正方形ABCD的边长为6,点E,F分别在AB,AD上,若CE=3,且∠ECF=45°,则CF的长为 ( )图X1-8A.2B.3C. D.二、填空题(每小题4分,共24分)11.一组数据2,3,3,5,7的中位数是,方差是.12.如图X1-9是一个斜体的“土”字,AB∥CD,已知∠1=75°,则∠2= °.图X1-913.为了了解某毕业班学生的睡眠时间情况,小红随机调查了该班15名同学,结果如下表:每天睡眠时间7 7.5 8 8.5 9 (单位:小时)人数 2 4 5 3 1 则这15名同学每天睡眠时间的众数是小时,中位数是小时.14.如图X1-10,将弧长为6π的扇形纸片AOB围成圆锥形纸帽,使扇形的两条半径OA与OB重合(粘连部分忽略不计),则圆锥形纸帽的底面圆半径是.图X1-1015.如图X1-11,已知点B,D在反比例函数y=(a>0)的图象上,点A,C在反比例函数y=(b<0)的图象上,AB∥CD∥x轴,AB,CD在x轴的同侧,AB=4,CD=3,AB与CD间的距离为1,则a-b的值是.图X1-1116.如图X1-12,点A(2,0),以OA为半径在第一象限内作圆弧AB,使∠AOB=60°,点C为弧AB 的中点,D为半径OA上一动点(不与点O,A重合),点A关于直线CD的对称点为E,若点E落在半径OA上,则点E的坐标为;若点E落在半径OB上,则点E的坐标为.图X1-12|加加练|1.计算:+20170-(-)-1+3tan30°+.2.解方程:+=3.3.先化简,再求值:2b2+(a+b)(a-b)-(a-b)2,其中a=-3,b=.参考答案1.C2.A3.B4.B5.B6.C7.C8.D9.B10.A11.312.10513.8814.315.1216.(2-2,0)(-1,3-)加加练1.解:原式=2-+1-(-3)+3×+2=6+2.2.解:去分母得x+(-2)=3(x-1),∴2x=1,∴x=.经检验,x=是原方程的解,∴原方程的解为x=.3.解:原式=2b2+a2-b2-(a2-2ab+b2)=a2+b2-a2+2ab-b2=2ab.∵a=-3,b=,∴原式=2×(-3)×=-3.选择填空限时练(二)[限时:40分钟满分:54分]一、选择题(每小题3分,共30分)1.某小区经过改进用水设施,5年内小区居民累计节水39400吨,将39400用科学记数法表示为( )A.3.9×104B.3.94×104C.39.4×103D.4.0×1042.下列运算正确的是( )A.(-3)2=-9B.(-1)2015×1=-1C.-5+3=8D.-|-2|=23.下列图形中是轴对称图形但不是中心对称图形的是( )A.等边三角形B.平行四边形C.矩形D.圆4.不等式3x<2(x+2)的解是( )A.x>2B.x<2C.x>4D.x<45.已知一组数据0,-1,1,2,3,则这组数据的方差为( )A.0B.1C.D.26.在Rt△ABC中,两直角边的长分别为6和8,则其斜边上的中线长为( )A.10B.3C.4D.57.在☉O中,圆心O到弦AB的距离为AB长度的一半,则弦AB所对圆心角的大小为( )A.30°B.45°C.60°D.90°8.已知点C是线段AB的黄金分割点(AC>BC),则下列结论正确的是( )A.AB2=AC2+BC2B.BC2=AC·BAC.=D.=9.如图X2-1,D是等边三角形ABC边AB上的一点,且AD∶DB=1∶2,现将△ABC折叠,使点C 与D重合,折痕为EF,点E,F分别在AC和BC上,则CE∶CF= ( )图X2-1A. B. C. D.10.若二次函数y=ax2+bx+c(a≠0)的图象与x轴的交点坐标分别为(x1,0),(x2,0),且x1<x2,图象上有一点M(x0,y0)在x轴下方,对于以下说法:①b2-4ac>0;②x=x0是方程ax2+bx+c=y0的解;③x1<x0<x2;④a(x0-x1)(x0-x2)<0.其中正确的是( )A.①③④B.①②④C.①②③D.②③二、填空题(每小题4分,共24分)11.请写出一个解为x=1的一元一次方程: .12.计算:2tan60°+(2-)0-()-1= .13.二次函数y=x2+4x+5(-3≤x≤0)的最大值是,最小值是.14.当1<a<2时,代数式+|1-a|= .15.如图X2-2,已知点A1,A2,…,A n均在直线y=x-1上,点B1,B2,…,B n均在双曲线y=-上,并且满足:A1B1⊥x轴,B1A2⊥y轴,A2B2⊥x轴,B2A3⊥y轴,…,A n B n⊥x轴,B n A n+1⊥y轴,…,记点A n的横坐标为a n(n为正整数).若a1=-1,则a3= ,a2015= .图X2-216.如图X2-3,在边长为2的菱形ABCD中,∠A=60°,M是AD边的中点,N是AB边上一动点,将△AMN沿MN所在的直线翻折得到△A'MN,连结A'C,则A'C长度的最小值是.图X2-3参考答案1.B2.B3.A4.D5.D6.D7.D8.C9.A10.B11.x-1=0(答案不唯一)12.2-113.5 114.115.216.-1选择填空限时练(三)[限时:40分钟满分:54分]一、选择题(每小题3分,共30分)1.-5的绝对值等于( )A.5B.-5C. D.-2.下列几何体中,俯视图为三角形的是( )图X3-13.事件:在只装有2个红球和8个黑球的袋子里,摸出一个白球是( )A.可能事件B.随机事件C.不可能事件D.必然事件4.下列运算正确的是( )A.(2a2)3=6a6B.-a2b2·3ab3=-3a2b5C.+=-1D.·=-15.在一次中学生田径运动会上,参加男子跳高的20名运动员的成绩如下表:成绩/米 1.55 1.60 1.65 1.70 1.75 1.80 人数 4 3 5 6 1 1 则这些运动员成绩的众数为( )A.1.55米B.1.65米C.1.70米D.1.80米6.已知点(-2,y1),(3,y2)在一次函数y=2x-3的图象上,则y1,y2,0的大小关系是( )A.y1<y2<0B.y1<0<y2C.y2<0<y1D.0<y1<y27.如图X3-2,一架长2.5米的梯子AB斜靠在墙上,已知梯子底端B到墙角C的距离为1.5米,设梯子与地面所夹的锐角为α,则cosα的值为( )图X3-2A. B. C. D.8.我们知道方程组的解是现给出另一个方程组它的解是( )A. B.C. D.9.七巧板是我们祖先的一项卓越创造,被誉为“东方魔板”.如图X3-3是一个七巧板迷宫,它恰好拼成了一个正方形ABCD,其中E,P分别是AD,CD的中点,一只蚂蚁从点A处沿图中实线爬行到出口点P处.若AB=2,则它爬行的最短路程为( )图X3-3A. B.1+C.2D.310.如图X3-4,在▱ABCD中,∠DAB=60°,AB=10,AD=6,☉O分别切边AB,AD于点E,F,且圆心O 恰好落在DE上.现将☉O沿AB方向滚动到与边BC相切(点O在▱ABCD的内部),则圆心O移动的路径长为( )图X3-4A.4B.6C.7-D.10-2二、填空题(每小题4分,共24分)11.分解因式:ab+ac= .12.小红同学5月份各项消费情况的扇形统计图如图X3-5,其中小红在学习用品上支出100元,则在午餐上支出元.图X3-513.如图X3-6,在☉O中,C为优弧AB上一点,若∠ACB=40°,则∠AOB= 度.图X3-614.甲、乙两工程队分别承接了250米,150米的道路铺设任务,已知乙比甲每天多铺设5米,甲完成铺设任务的时间是乙的2倍.设甲每天铺设x米,则根据题意可列出方程: .15.如图X3-7,点A在第一象限,作AB⊥x轴,垂足为点B,反比例函数y=的图象经过AB的中点C,过点A作AD∥x轴,交该函数图象于点D.E是AC的中点,连结OE,将△OBE沿直线OE对折到△OB'E,使OB'恰好经过点D,若B'D=AE=1,则k的值是.图X3-716.如图X3-8,矩形ABCD和正方形EFGH的中心重合,AB=12,BC=16,EF=,分别延长FE,GF,HG和EH交AB,BC,CD,AD于点I,J,K,L.若tan∠ALE=3,则AI的长为,四边形AIEL的面积为.图X3-8|加加练|1.计算:(-2018)0+-9×.2.化简:(a+2)(a-2)-a(a+1).3.化简:+.参考答案1.A2.C3.C4.C5.C6.B7.A8.D9.B[解析] ∵正方形ABCD,E,P分别是AD,CD的中点,AB=2,∴AE=DE=DP=1,∠D=90°,∴EP==,∴蚂蚁从点A沿图中实线爬到出口点P处,爬行的最短路程为AE+EP=1+.故选B.10.B[解析] 连结OA,OF.∵AB,AD分别与☉O相切于点E,F,∴OE⊥AB,OF⊥AD,∴∠OAE=∠OAD=30°.在Rt△ADE中,AD=6,∠ADE=30°,∴AE=AD=3,∴OE=AE·=.∵AD∥BC,∠DAB=60°,∴∠ABC=120°.设当运动停止时,☉O与BC,AB分别相切于点M,N,连结ON,OM,OB.则∠BON=30°,且ON=,∴BN=ON·tan 30°=1,EN=AB-AE-BN=10-3-1=6.∴圆心O移动的路径长为6.11.a(b+c)12.20013.8014.=15.12[解析] 如图,过D作DF⊥OB于F,设B'E与AD交于点G.∵AB⊥x轴,AD∥x轴,∴四边形ABFD是矩形,由折叠可得,∠B'=90°=∠A.又∵B'D=AE=1,∠DGB'=∠EGA,∴△DB'G≌△EAG,∴DG=EG,B'G=AG,∴AD=B'E=BE.又∵E是AC的中点,C是AB的中点,∴AE=CE=1,AC=BC=2,∴BE=3=AD,AB=4=DF.设C(a,2),则D(a-3,4).∵反比例函数y=的图象经过点C,D,∴2a=4(a-3),解得a=6,∴C(6,2),∴k=6×2=12.16.5[解析] 如图,过点E作EM⊥AB于点M,过点F作FN⊥AB于点N,过点E作EA1⊥AD于点A1,交FN于Q,过点G作GA2⊥AD,过点H作HP⊥A1E于P,∵tan∠1=3,∴tan∠2=3.又∵EF=,∴EQ=1,QF=3.∵矩形ABCD与正方形EFGH的中心重合,∴AA1=A2D=6,A1A2=4=PQ.同理得AN=8,NB=4,EM=6.易证△IME∽△EQF,∴=,∴IM=2,∴IB=7,∴AI=5.∴A1E=7,∴A1L=,∴四边形AIEL的面积为+=×(5+7)×6+×7×=.加加练1.解:原式=1+2-9×=2.2.解:原式=a2-4-a2-a=-4-a.3.解:原式===a.选择填空限时练(四)[限时:40分钟满分:54分]一、选择题(每小题3分,共30分)1.下列四个数:-1,0,,3.14,其中为无理数的是( )A.-1B.0C.D.3.142.下列计算正确的是( )A.x3+x4=x7B.x3-x4=x-1C.x3·x4=x7D.x3÷x4=x3.如图X4-1所示的支架的主视图是 ( )图X4-1图X4-24.如图X4-3,电路图上有四个开关A,B,C,D和一个小灯泡,闭合开关D或同时闭合开关A,B,C 都可使小灯泡发光,则任意闭合其中两个开关,小灯泡发光的概率是( )图X4-3A. B.C. D.5.如图X4-4,已知直线AB∥CD,∠GEB的平分线EF交CD于点F,∠1=60°,则∠2等于( )图X4-4A.130°B.140°C.150°D.160°6.若a-b=2ab,则-的值为 ( )A.-2B.-C.D.27.若将直尺的0 cm刻度线与半径为5 cm的量角器的0°线对齐,并让量角器沿直尺的边缘无滑动地滚动(如图X4-5),则直尺上的10 cm刻度线对应量角器上的度数约为( )图X4-5A.90°B.115°C.125°D.180°8.在某次体育测试中,九年级一班女同学的一分钟仰卧起坐成绩(单位:个)如下表:成绩45 46 47 48 49 50 人数 1 2 4 2 5 1 这次测试成绩的中位数和众数分别为( )A.47,49B.48,49C.47.5,49D.48,509.如图X4-6,在矩形ABCD中,AB=3,BC=5,点P是BC边上的一个动点(点P不与点B,C重合),现将△PCD沿直线PD折叠,使点C落到点C'处;作∠BPC'的平分线交AB于点E.设BP=x,BE=y,则下列图象中,能表示y与x的函数关系的大致图象是 ( )图X4-6图X4-710.如图X4-8,已知在平面直角坐标系中,直线l1⊥x轴于点A(2,0),点B是直线l1上的动点,直线l2:y=x+1交l1于点C,过点B作直线l3垂直于l2,垂足为D,过点O,B的直线l4交l2于点E.设直线l1,l2,l3围成的三角形的面积为S1,直线l2,l3,l4围成的三角形的面积为S2,且S2=S1,则∠BOA的度数为 ( )图X4-8A.15°B.30°C.15°或30°D.15°或75°二、填空题(每小题4分,共24分)11.分解因式:a2-4b2= .12.二次根式中,x的取值范围是.13.如图X4-9,把正三角形ABC的外接圆对折,使点A落在的中点F处,若BC=6,则折痕在△ABC内的部分DE的长为.图X4-914.如图X4-10,在边长为2的菱形ABCD中,∠ABC=120°,E,F分别为AD,CD上的动点,且AE+CF=2,则线段EF长的最小值是.图X4-1015.如图X4-11,一段抛物线:y=-x(x-3)(0≤x≤3),记为C1,它与x轴交于点O,A1;将C1绕点A1旋转180°得C2,交x轴于点A2;将C2绕点A2旋转180°得C3,交x轴于点A3;…;若P(m,2)在第3段抛物线C3上,则m= .图X4-1116.对于两个不相等的实数a,b,我们规定符号max{a,b}表示a,b中较大的数,如max{2,4}=4.按照这个规定,方程max{x,-x}=的解为.|加加练|1.计算:(-)2+|-4|×2-1-(-1)0.2.解不等式:3x-1≥2(x-1),并把它的解集在数轴上表示出来.图X4-123.化简:+.参考答案1.C2.C3.D4.A5.C6.A7.B8.B9.D10.D11.(a+2b)(a-2b)12.x≤13.414.15.7或816.x=1+或x=-1加加练1.解:原式=3+4×-1=3+2-1=4.2.解:去括号,得3x-1≥2x-2.移项、合并同类项,得x≥-1.把不等式的解集在数轴上表示出来,如图:3.原式=+=+=.选择填空限时练(五)[限时:40分钟满分:54分]一、选择题(每小题3分,共30分)1.下列四个实数,2,0,-1,其中负数是( )A. B.2 C.0 D.-12.下列计算,结果等于a4的是( )A.a+3aB.a5-aC.(a2)2D.a8÷a23.如图X5-1所示,该圆柱体的左视图是( )图X5-1图X5-24.如图X5-3,△ABC内接于☉O,∠A=68°,则∠OBC等于( )图X5-3A.22°B.26°C.32°D.34°5.某校数学兴趣小组在一次数学课外活动中,随机抽查了该校10名同学参加今年初中学业水平考试的体育成绩,统计结果如下表:成绩/分36 37 38 39 40 人数/人 1 2 1 4 2 表中表示成绩的数据中,中位数是( )A.38分B.38.5分C.39分D.39.5分6.用配方法解一元二次方程x2-6x-10=0,变形正确的是 ( )A.(x-3)2=19B.(x+3)2=19C.(x-3)2=1D.(x+3)2=17.不等式组的解集是( )A.x≥2B.1<x<2C.1<x≤2D.x≤28.已知点(-1,y1),(1,0),(3,y2)都在一次函数y=kx-2的图象上,则y1,y2,0的大小关系是( )A.0<y1<y2B.y1<0<y2C.y1<y2<0D.y2<0<y19.如图X5-4,AB是半圆O的直径,半径OC⊥AB于点O,点D是的中点,连结CD,AD,OD,给出以下四个结论:①∠DOB=∠ADC;②CE=OE;③△ODE∽△ADO;④2CD2=CE·AB.其中正确结论的序号是( )图X5-4A.①③B.②④C.①④D.①②③10.如图X5-5,矩形ABCD中,AB=8,BC=6,将矩形ABCD绕点A按逆时针方向旋转得到矩形AEFG,AE,FG分别交射线CD于点P,H,连结AH.若P是CH的中点,则△APH的周长为 ( )图X5-5A.15B.18C.20D.24二、填空题(每小题4分,共24分)11.分解因式:a2-4a= .12.一个布袋里装有10个只有颜色不同的球,其中红球有m个,从布袋中随机摸出一个球记下颜色后放回、搅匀,再摸出一个球,通过大量重复试验后发现,摸到红球的频率稳定在0.3左右,则m的值为.13.某种品牌手机经过4,5月份连续两次降价,每部售价由5000元降到3600元.已知5月份降低的百分率是4月份降低的百分率的2倍,设4月份降低的百分率为x,根据题意可列方程: .14.如图X5-6,用一个半径为60 cm,圆心角为150°的扇形围成一个圆锥,则这个圆锥的底面半径为cm.图X5-615.如图X5-7,把菱形ABCD沿折痕AH翻折,使B点落在BC延长线上的点E处,连结DE.若∠B=30°,则∠CDE= °.图X5-716.如图X5-8,直角坐标系xOy中,直线y=-x+b分别交x,y轴的正半轴于点A,B,交反比例函数y=-的图象于点C,D(点C在第二象限内),过点C作CE⊥x轴于点E,记四边形OBCE的面积为S1,△OBD的面积为S2,若=,则CD的长为.图X5-8|加加练|1.计算:(-2)0-()2+|-1|.2.解不等式组:3.解方程:-1=.参考答案1.D2.C3.C4.A5.C6.A7.C8.B9.C10.C11.a(a-4)12.313.5000(1-x)(1-2x)=360014.2515.4516.5加加练1.解:原式=1-6+1=-4.2.解:解不等式①,得x>-3,解不等式②,得x<5,∴不等式组的解是-3<x<5.3.解:原方程可化为2-(x-2)=3x,解得x=1.经检验,x=1是原方程的解.所以原方程的解是x=1.选择填空限时练(六)[限时:40分钟满分:54分]一、选择题(每小题3分,共30分)1.下列四个数中,是正整数的是 ( )A.-1B.0C. D.12.据媒体报道,我国因环境污染造成的巨大经济损失,每年高达680000000元,这个数用科学记数法表示正确的是( )A.6.8×109元B.6.8×108元C.6.8×107元D.68×107元3.下列事件中,必然事件是 ( )A.今年夏季的雨量一定多B.下雨天每个人都打着伞C.二月份有30天D.我国冬季的平均气温比夏季的平均气温低4.如图X6-1,点A,B,C,D,O都在方格纸的格点上,若△COD是由△AOB绕点O按逆时针方向旋转而得,则旋转的角度为( )图X6-1A.30°B.45°C.90°D.135°5.一次函数y=2x-2的图象不经过的象限是( )A.第一象限B.第二象限C.第三象限D.第四象限6.下列四个图形,其中是轴对称图形,且对称轴的条数为2的图形的个数是( )图X6-2A.1个B.2个C.3个D.4个7.对于反比例函数y=,下列说法不正确的是( )A.点(-3,-1)在它的图象上B.它的图象在第一,三象限C.y随x的增大而减小D.当x>1时,y<38.如图X6-3,在菱形ABCD中,对角线AC,BD相交于点O,E为BC的中点,则下列式子一定成立的是( )图X6-3A.AC=2OEB.BC=2OEC.AD=OED.OB=OE9.如图X6-4,将长为2,宽为1的矩形纸片分割成n个三角形后,拼成面积为2的正方形,则n≠( )图X6-4A.2B.3C.4D.510.小阳在如图X6-5①的扇形舞台上沿O➝M➝N匀速行走,他从点O出发,沿箭头所示的方向经过点M再走到点N,共用时70秒.有一台摄像机选择了一个固定的位置记录了小阳的走路过程,设小阳走路的时间为t(单位:秒),他与摄像机的距离为y(单位:米),表示y与t的函数关系的图象大致如图X6-5②,则这个固定位置可能是图X6-5①中的( )图X6-5A.点QB.点PC.点MD.点N二、填空题(每小题4分,共24分)11.使代数式有意义的x的取值范围是.12.东山茶厂有甲、乙、丙三台包装机,同时分装质量为200克的茶叶.从它们各自分装的茶叶中分别随机抽取了15盒,测得它们的实际质量的方差如下表:甲包装机乙包装机丙包装机方差(克2) 5.6 9.3 0.9 根据表中数据,三台包装机中, 包装机包装的茶叶质量最稳定.13.如图X6-6,l1是反比例函数y=在第一象限内的图象,且过点A(2,1),l2与l1关于x轴对称,那么图象l2的函数解析式为(x>0).图X6-614.将一个三角形经过放大后得到另一个三角形,如果所得三角形在原三角形的外部,这两个三角形各对应边平行且距离都相等,那么我们把这样的两个三角形叫做“等距三角形”,它们对应边之间的距离叫做“等距”.如果两个等边三角形是“等距三角形”,它们的“等距”是1,那么它们周长的差是.15.已知在平面直角坐标系内,以点P(1,2)为圆心,r为半径画圆,☉P与坐标轴恰好有三个交点,那么r的取值是.16.在平面直角坐标系xOy中,抛物线y=-x2+2mx-m2-m+1交y轴于点A,顶点为D,对称轴与x 轴交于点H.(1)顶点D的坐标为(用含m的代数式表示);(2)当抛物线顶点D在第二象限时,如果∠ADH=∠AHO,那么m的值为.|加加练|1.计算:3-2-2cos60°+(12-2006)0-|-|.2.先化简,再求值:(1-)÷,其中x请从-2,-1,0,1,2中选一个恰当的数.参考答案1.D2.B3.D4.C5.B6.C7.C8.B9.A10.B11.x≥-112.丙13.y=-14.615.或216.(1)(m,1-m)(2)m=-1或m=-2加加练1.解:原式=-2×+1-=-.2.解:原式=÷=·=x+2.∵x≠0,1,-2,∴x可取-1或2.当x=2时,原式=2+2=4.(或当x=-1时,原式=-1+2=1)选择填空限时练(七)[限时:40分钟满分:54分]一、选择题(每小题3分,共30分)1.计算(-6)+5的结果是( )A.-11B.11C.-1D.12.函数y=中,自变量x的取值范围是( )A.x≠2B.x≥2C.x>2D.x≥-23.在以下“绿色食品”“节能减排”“循环回收”“质量安全”四个标志中,是轴对称图形的是( )图X7-14.如图X7-2是由4个相同的正方体搭成的几何体,则其俯视图是( )图X7-2图X7-35.一个不透明的布袋中有2个白球,3个黑球,除颜色外其他都相同,从中随机摸出一个球,恰好为黑球的概率是( )A. B. C. D.6.如图X7-4,矩形ABCD的两条对角线交于点O,若∠AOD=120°,AB=6,则AC等于( )图X7-4A.8B.10C.12D.187.不等式2(x-1)≥x的解在数轴上表示为( )图X7-58.如图X7-6,已知D,E分别是△ABC的边AB,AC上的点,DE∥BC,且BD=3AD,那么AE∶AC等于( )图X7-6A.2∶3B.1∶2C.1∶3D.1∶49.如图X7-7,已知正方形ABCD的边长为1,分别以顶点A,B,C,D为圆心,1为半径画弧,四条弧交于点E,F,G,H,则图中阴影部分的外围周长为( )图X7-7A.πB.πC.πD.π10.把三张大小相同的正方形卡片A,B,C叠放在一个底面为正方形的盒底上,底面未被卡片覆盖的部分用阴影表示.若按图X7-8①,②摆放,阴影部分的面积分别为S1和S2,则S1和S2的大小关系是( )图X7-8A.S1=S2B.S1<S2C.S1>S2D.无法确定二、填空题(每小题4分,共24分)11.分解因式:ab-2a= .12.已知一组数据:2,1,-1,0,3,则这组数据的中位数是.13.在同一平面直角坐标系内,将函数y=2x2-3的图象向右平移2个单位,再向下平移1个单位后得到新图象的顶点坐标是.14.如图X7-9,将Rt△ABC绕直角顶点A顺时针旋转90°,得到△AB'C',连结BB',若∠1=25°,则∠C的度数是.图X7-915.如图X7-10,在平面直角坐标系中,直线y=kx+b与x轴,y轴分别交于点A(4,0),B(0,2),点C为线段AB上任意一点,过点C作CD⊥OA于点D,延长DC至点E使CE=DC,作EF⊥y轴于点F,则四边形ODEF的周长为.图X7-1016.如图X7-11,已知AB,CD是☉O的两条相互垂直的直径,E为半径OB上一点,且BE=3OE,延长CE交☉O于点F,线段AF与DO交于点M,则的值是.图X7-11|加加练|1.计算:-2cos 45°+()-1.2.化简:+.3.求满足不等式组的所有整数解.参考答案1.C2.B3.A4.A5.C6.C7.C8.D9.B10.A11.a(b-2)12.113.(2,-4)14.70°15.816.加加练1.解:原式=2-2×+2=+2.2.解:原式====2.3.解:解x-3(x-2)≤8,得x≥-1,解x-1<3-x,得x<2,所以不等式组的解集为-1≤x<2,其中所有的整数解为-1,0,1.选择填空限时练(九)[限时:40分钟满分:54分]一、选择题(每小题3分,共30分)1.在-2,0,,1这四个数中,最大的数是( )A.-2B.0C.D.12.如图X9-1是由几个相同的小正方体搭成的一个几何体,它的俯视图是( )图X9-1图X9-23.抽样调查某公司员工的年收入数据(单位:万元),结果如下表:年收入/万元 5 6 7 15 30 人数8 6 3 2 1 则可以估计该公司员工中等年收入约为( )A.5万元B.6万元C.6.85万元D.7.85万元4.C919大型客机是中国具有自主知识产权的干线民用飞机,其零部件总数超过100万个,将100万用科学记数法表示为( )A.1×106B.100×104C.1×107D.0.1×1085.如图X9-3,AB是☉O的弦,OC⊥AB,交☉O于点C,连结OA,OB,BC,若∠ABC=20°,则∠AOB的度数是( )图X9-3A.40°B.50°C.70°D.80°6.不等式的解x≤2在数轴上表示为 ( )图X9-47.如图X9-5,在△ABC中,两条中线BE,CD相交于点O,则S△DOE∶S△COB等于( )图X9-5A.1∶2B.1∶3C.1∶4D.2∶38.小明进行两次定点投篮练习,第一次a投b中(a≥b),第二次c投d中(c≥d),用新运算“ ”描述小明两次定点投篮总体命中率,则下列算式合理的是( )A. =B. =C. =D. =9.如图X9-6,抛物线y1=-(x+2)2-1与y2=a(x-4)2+3交于第四象限点A(1,-4),过点A作x轴的平行线,分别交两条抛物线于B,C两点,且D,E分别为顶点.则下列结论正确的是 ( )图X9-6A.AB<ACB.当x>1时,y1>y2C.△ACE是等边三角形D.△ABD是等腰三角形10.如图X9-7,菱形ABCD中,∠ABC=60°,边长为3,P是对角线BD上的一个动点,则BP+PC的最小值是( )图X9-7A. B.C.3D.+二、填空题(每小题4分,共24分)11.分解因式:2m2-8= .12.如图X9-8,把一张长方形纸带沿着直线GF折叠,若∠CGF=30°,则∠1的度数是.图X9-813.某城市为了了解本市男女青少年平均身高发育情况,随机调查了6岁~18岁男女青少年各100人,制作成如图X9-9所示的不同年龄平均身高统计图,从图中可知,该城市的男性青少年的身高高于同年龄女性的年龄段大概是.图X9-914.如图X9-10,P是边长为a的等边三角形ABC内任意一点,过点P分别作三角形三边的垂线PD,PE,PF,垂足分别点为D,E,F,则图中阴影部分图形的面积总和为(用含a的式子表示) .图X9-1015.如图X9-11,正方形ABCD的边长为4,在这个正方形内作等边三角形EFG,使它们的中心重合,则△EFG的顶点到正方形ABCD的顶点的最短距离是.图X9-1116.下面是一种算法:输入任意一个数x,都是“先乘2,再减去3”,进行第1次这样的运算,结果为y1,再对y1实施同样的运算,称为第2次运算,结果为y2,这样持续进行,要使第n次运算结果为0,即y n=0,则最初输入的数应该是.(用含有n的代数式表示)|加加练|1.化简:÷(-1).2.[2018·成都 ]为了美化环境,建设宜居成都,我市准备在一个广场上种植甲、乙两种花卉.经市场调查,甲种花卉的种植费用y(元)与种植面积x(m2)之间的函数关系如图X9-12,乙种花卉的种植费用为每平方米100元.(1)直接写出当0≤x≤300和x>300时,y与x的函数关系式.(2)广场上甲、乙两种花卉种植面积共1200 m2,若甲种花卉的种植面积不少于200 m2,且不超过乙种花卉种植面积的2倍,那么应该怎样分配甲、乙两种花卉的种植面积才能使种植总费用最少?最少费用为多少元?1.D2.D3.B4.A5.D6.B7.C8.C9.D10.B[解析] 如图,过点P作PM⊥AB于点M,过点C作CH⊥AB于点H.∵四边形ABCD是菱形,∠ABC=60°,∴∠PBM=∠ABC=30°,∴PM=PB,∴PB+PC=PC+PM.根据垂线段最短可知,CP+PM的最小值为CH的长.在Rt△CBH中,CH=BC·sin 60°=,∴PB+PC的最小值为.故选B.11.2(m+2)(m-2)12.60°13.6~10岁和14~18岁14.15.4-216.加加练1.解:原式=÷=·=.2.解:(1)当0≤x≤300时,设函数关系式为y=k1x,过(300,39000),则39000=300k1,解得k1=130.∴当0≤x≤300时,y=130x;当x>300时,设函数关系式为y=k2x+b,过(300,39000)和(500,55000)两点,∴解得∴y=80x+15000.综上y=(2)设甲种花卉的种植面积为a m2,则乙种花卉的种植面积为(1200-a) m2.根据题意得解得200≤a≤800.当200≤a≤300时,总费用W1=130a+100(1200-a)=30a+120000,当a=200时,总费用最少为W min=30×200+120000=126000(元);当300<a≤800时,总费用W2=80a+15000+100(1200-a)=-20a+135000,当a=800时,总费用最少为W min=-20×800+135000=119000(元).∵119000<126000,∴当a=800时,总费用最少,为119000元,此时1200-a=400.答:当甲、乙两种花卉种植面积分别为800 m2和400 m2时,种植总费用最少,最少费用为119000元.。
2021年浙江中考数学总复习选择填空提分特训(含答案)
选择填空提分特训(七)[限时:40分钟 满分:54分]一、选择题(每小题3分,共30分) 1.-5的倒数是 ( ) A .-5B .5C .-15D .152.-32的结果等于 ( ) A .9B .-9C .-1D .-6 3.下列各项中,加上4x 2+1,能成为(a+b )2的形式的是 ( ) A .4B .-2xC .4x 4D .16x 44.点(-1,2)关于原点的对称点的坐标为 ( )A .(1,-2)B .(-1,-2)C .(1,2)D .(2,-1)5.某校开展了“空中云班会”的满意度调査,其中九年级各班满意的人数分别为27,28,28,29,29,30.下列关于这组数据描述正确的是 ( )A .中位数为29B .众数为28C .平均数为28.5D .方差为26.下列四个代数式:1x 2+3;√4-x ;x 0;√-x 3中,无论x 取何实数,都有意义的有 ( ) A .1个B .2个C .3个D .4个7.如果把1,3,6,10…这样的数称为“三角形数”,而把1,4,9,16…这样的数称为“正方形数”.从图X7-1中可以发现,任何一个大于1的“正方形数”都可以看作两个相邻“三角形数”之和.下列等式中,符合这一规律的是( )图X7-1A.13=3+10B.25=9+16C.49=18+31D.36=15+218.如图X7-2,甲、乙两楼相距30米,乙楼高度为36米,自甲楼顶A处看乙楼顶B处仰角为30°,则甲楼高度为()图X7-2A.11米B.(36-15√3)米C.15√3米D.(36-10√3)米9.如图X7-3,在四边形ABCD中,AB=CD,AC,BD是对角线,E,F,G,H分别是AD,BD,BC,AC的中点,连结EF,FG,GH,HE,则四边形EFGH的形状是()图X7-3A.平行四边形B.矩形C.菱形D.正方形(x>0)上的一点,过A作AB⊥x轴,垂足为B,点P从点B处出发,沿x轴匀速10.如图X7-4,已知点A是双曲线y=4x向右运动t秒(t>0),同时点Q从点A处出发,以与P点相同的速度沿双曲线向右运动t秒(t>0),连结OQ,PQ,得△OPQ,则△OPQ的面积随着t的增大而()图X7-4A.增大B.减小C.不变D.先增大再减小二、填空题(每小题4分,共24分)11.分解因式:a2b-2ab=.12.如图X7-5,在边长相同的小正方形组成的网格中,点A,B,C都在这些小正方形的顶点上,则tan∠ABC的值为.图X7-513.在两个暗盒中,各自装有编号为1,2,3的三个球,球除编号外无其他区别,则在两个暗盒中各取一个球,两球上的编号的积为奇数的概率为.14.如图X7-6,在△ABC中,点D在BC边上,BD=AD=AC,E为CD的中点.若∠CAE=18°,则∠B为.图X7-615.如图X7-7,点D,E,F,G分别是△ABC的边AB,BC上的点,BD=AE,DG∥EF∥AC.若S四边形DEFG =2(S△BDG+S四边形ACFE),则BD∶DE=.图X7-716.如图X7-8,在Rt△ABC中,∠C=90°,∠A=30°,BC=2,线段BC的垂直平分线分别交BC,AB于点D,E,P是直线DE上的一个动点.(1)点P离△ABC的外心的最近距离是;(2)当∠P AC=∠PBC时,PD=.图X7-8附加训练17.已知4x=3y,求代数式(x-2y)2-(x-y)(x+y)-2y2的值.18.化简:a2-b2a2b+ab2÷a2+b22ab-1.19.如图X7-9,在菱形ABCD中,点E,F分别在BC,CD上,且CE=CF.(1)求证:△ABE≌△ADF;(2)若∠B=50°,AE⊥BC,求∠AEF的度数.图X7-9【参考答案】1.C2.B3.C4.A5.C6.B7.D8.D9.C10.A[解析] 如图,过点Q作QM⊥x轴,垂足为M,根据移动速度和距离可知,点M一定在点P的左侧,即MQ一定在△OPQ的内部,S△OPQ>S△OQM.∵S△OQM=S△OAB=12|k|=2,∴S△OPQ>2,在向右运动的过程中,MP增长的速度要大于QM减小的速度,因此S△PQM逐渐增大,故选A.11.ab(a-2)12.1213.4914.36°15.1∶416.(1)0(2)2-√3或√3−√2或√3+√2[解析] (1)易知△ABC的外心在直线DE上.∵P是直线DE上的一个动点,∴点P离△ABC的外心的最近距离是0.(2)∵∠C=90°,∠BAC=30°,BC=2,∴AC=BCtan30°=2√3.∵D是CB的中点,∴CD=BD=1.当点P在△ABC内部时,如图①,过点A作AF⊥DE于点F,则四边形AFDC是矩形,∴AC =DF ,AF =CD ,DF ∥AC , ∴∠P AC =∠APF .∵∠P AC =∠PBC ,∴∠APF =∠PBC. ∵∠AFP =∠PDB =90°,∴△AFP ∽△PDB , ∴AFPD =PFDB .设PD =x ,则PF =DF -PD =2√3-x ,∴1x =2√3-x1,解得x =√3±√2,∴DP =√3+√2或√3−√2. 当点P 在△ABC 外部时,如图②,过点A 作AF ⊥PD 于点F ,同理可得△AFP ∽△PDB , ∴AFPD =PFDB .设PD =y ,则PF =DF +PD =2√3+y ,∴1y =2√3+y 1, 解得,y =2-√3,(y =-√3-2,舍去),∴DP =2-√3. 故答案为:2-√3或√3−√2或√3+√2.17.解:原式=x 2-4xy +4y 2-x 2+y 2-2y 2=3y 2-4xy.当4x =3y 时,原式=3y 2-3y 2=0. 18.解:原式=(a+b )(a -b )ab (a+b )÷(a -b )22ab=(a+b )(a -b )ab (a+b )·2ab (a -b )2=2a -b .19.解:(1)证明:在菱形ABCD 中,AB =BC =CD =DA ,∠B =∠D ,∵CE=CF,∴BE=DF,∴△ABE≌△ADF(SAS).(2)∵AE⊥BC,∴∠AEB=90°.∵∠B=50°,∴∠BAE=40°.∵△ABE≌△ADF,∴∠DAF=∠BAE=40°.∵AD∥BC,∴∠BAD=130°,∴∠EAF=50°.∵△ABE≌△ADF,∴AE=AF,∴∠AEF=(180°-50°)÷2=65°.。
2021九年级数学中考总复习专题选择填空专项训练解题指导培优试题含答案解析
2021九年级数学中考总复习专题选择填空专项训练解题指导培优试题含答案解析1．如图，已知矩形ABCD沿着直线BD折叠，使点C落在C′处，BC′交AD于E，AD＝8，AB＝4，则DE的长为（）A．3B．4C．5D．62．如图，正方形纸片ABCD的边长为3，点E、F分别在边BC、CD上，将AB、AD分别沿AE、AF折叠，点B，D恰好都落在点G处，已知BE＝1，则EF的长为（）A．1.5B．2.5C．2.25D．33．如图，AB＝4，射线BM和AB互相垂直，点D是AB上的一个动点，点E在射线BM上，BE=12DB，作EF⊥DE，并截取EF＝DE，连接AF并延长交射线BM于点C，设BE＝x，BC＝y，则y关于x的函数解析式为．4．如图，在扇形OAB中，∠AOB＝110°，半径OA＝18，将扇形OAB沿着过点B的直线折叠，点O恰好落在AB̂上的点D处，折痕交OA于点C，则AD̂的长等于．（结果保留π）5．如图，在△ABC中，∠ABC＝60°，点P是△ABC内的一点，使得∠APB＝∠BPC＝∠CP A，且P A＝8，PC＝6，则PB＝．6．如图，在Rt△ABC中，∠ACB＝90°，∠B＝30°，AC＝2．作△ABC的高CD，作△CDB的高DC1，作△DC1B的高C1D1，…，如此下去，则得到的所有阴影三角形的面积之和为．7．如图所示，△ABC中，∠C＝90°，AC＝2，BC＝1，顶点A，C分别在x轴，y轴的正半轴上滑动，则点B到原点的最大距离是．8．如图，在平面直角坐标系xOy中，直线AB经过点A（﹣4，0）、B（0，4），⊙O的半径为1（O为坐标原点），点P在直线AB上，过点P作⊙O的一条切线PQ，Q为切点，则切线长PQ的最小值为．9．如图，已知一次函数y＝kx+b的图象经过点P（3，2），与反比例函数y=2x（x＞0）的图象交于点Q（m，n）．当一次函数y的值随x值的增大而增大时，m的取值范围是．10．如图，以扇形OAB的顶点O为原点，半径OB所在的直线为x轴，建立平面直角坐标系xOy，点B的坐标为（2，0），若抛物线y=12x2+k与扇形OAB的边界总有两个公共点，则实数k的取值范围是．中考总复习数学专题选择填空专项训练解题指导培优试题含答案解析一．试题（共11小题）1．如图，已知矩形ABCD 沿着直线BD 折叠，使点C 落在C ′处，BC ′交AD 于E ，AD ＝8，AB ＝4，则DE 的长为（ ）A ．3B ．4C ．5D ．6解：∵Rt △DC ′B 由Rt △DBC 翻折而成，∴CD ＝C ′D ＝AB ＝8，∠C ＝∠C ′＝90°，设DE ＝x ，则AE ＝8﹣x ，∵∠A ＝∠C ′＝90°，∠AEB ＝∠DEC ′，∴∠ABE ＝∠C ′DE ，在Rt △ABE 与Rt △C ′DE 中，{∠A =∠C′=90°AB =C′D ∠ABE =∠C′DE，∴Rt △ABE ≌Rt △C ′DE （ASA ），∴BE ＝DE ＝x ，在Rt △ABE 中，AB 2+AE 2＝BE 2，∴42+（8﹣x ）2＝x 2，解得：x ＝5，∴DE 的长为5．故选：C ．2．如图，正方形纸片ABCD 的边长为3，点E 、F 分别在边BC 、CD 上，将AB 、AD 分别沿AE 、AF 折叠，点B ，D 恰好都落在点G 处，已知BE ＝1，则EF 的长为（ ）A．1.5B．2.5C．2.25D．3解：∵正方形纸片ABCD的边长为3，∴∠C＝90°，BC＝CD＝3，根据折叠的性质得：EG＝BE＝1，GF＝DF，设DF＝x，则EF＝EG+GF＝1+x，FC＝DC﹣DF＝3﹣x，EC＝BC﹣BE＝3﹣1＝2，∵在Rt△EFC中，EF2＝EC2+FC2，即（x+1）2＝22+（3﹣x）2，解得：x＝1.5，∴DF＝1.5，EF＝1+1.5＝2.5．故选：B．3．如图，AB＝4，射线BM和AB互相垂直，点D是AB上的一个动点，点E在射线BM上，BE=12DB，作EF⊥DE，并截取EF＝DE，连接AF并延长交射线BM于点C，设BE＝x，BC＝y，则y关于x的函数解析式为y=12x4−x（0＜x≤2）．解：作FM⊥BC于M．∵∠DBE＝∠DEF＝∠EMF＝90°，∴∠DEB+∠BDE＝90°，∠DEB+∠FEM＝90°，∴∠BDE＝∠FEM．在△DBE和△EMF中，{∠BDE =∠FEM ∠B =∠EMF DE =EF，∴△DBE ≌△EMF ，∴FM ＝BE ＝x ，EM ＝BD ＝2BE ＝2x ，∵FM ∥AB ，∴FM AB =CM CB， ∴x 4=y−3x y， ∴y =12x 4−x （0＜x ≤2）．4．如图，在扇形OAB 中，∠AOB ＝110°，半径OA ＝18，将扇形OAB 沿着过点B 的直线折叠，点O 恰好落在AB ̂上的点D 处，折痕交OA 于点C ，则AD ̂的长等于 5π ．（结果保留π）解：连结OD ，∵△BCD 是由△BCO 翻折得到，∴∠CBD ＝∠CBO ，∠BOD ＝∠BDO ，∵OD ＝OB ，∴∠ODB ＝∠OBD ，∴∠ODB ＝2∠DBC ，∵∠ODB +∠DBC ＝90°，∴∠ODB ＝60°，∵OD ＝OB∴△ODB 是等边三角形，∴∠DOB ＝60°，∵∠AOB ＝110°，∴∠AOD ＝∠AOB ﹣∠DOB ＝50°，∴弧AD 的长=50π×18180=5π．故答案为：5π．5．如图，在△ABC 中，∠ABC ＝60°，点P 是△ABC 内的一点，使得∠APB ＝∠BPC ＝∠CP A ，且P A ＝8，PC ＝6，则PB ＝ 4√3 ．解：由题意∠APB ＝∠BPC ＝∠CP A ＝120°，设∠PBC ＝α，∠ABC ＝60°则∠ABP ＝60°﹣α，∴∠BAP ＝∠PBC ＝α，∴△ABP ∽△BCP ，∴AP BP =BP PC ，BP 2＝AP •PC ，∴BP =√AP ⋅PC =√48=4√3．故答案是：4√3．6．如图，在Rt △ABC 中，∠ACB ＝90°，∠B ＝30°，AC ＝2．作△ABC 的高CD ，作△CDB 的高DC 1，作△DC 1B 的高C 1D 1，…，如此下去，则得到的所有阴影三角形的面积之和为 6√37．解：∵DC 1∥AC ，∴Rt △ACD ∽△CDC 1，同理可证：Rt △C 1D 1D ∽Rt △C 1D 1C 2，…；即白色部分的小直角三角形与阴影部分的小直角三角形逐一对应相似，∵如图，在Rt △ABC 中，∠ACB ＝90°，∠B ＝30°，AC ＝2，∴AB ＝2AC ＝4，BC =√AB 2−AC 2=2√3．在Rt △ABC 中，CD ⊥AB ，由S =12AC •BC =12AB •CD ，故CD =√3，∴AC ：CD ＝2：√3，∴白色部分小直角三角形的面积和：阴影部分小直角三角形的面积和＝AC 2：CD 2＝4：3， 故S 阴影=37S △ABC =37×12×2×2√3=6√37．故答案是：6√37．7．如图所示，△ABC 中，∠C ＝90°，AC ＝2，BC ＝1，顶点A ，C 分别在x 轴，y 轴的正半轴上滑动，则点B 到原点的最大距离是 √2+1 ．解：设AC 的中点是D ，则OD =12AC ＝1，根据勾股定理得BD =√2，当B 、D 、O 在一条直线上时，点B 到原点O 的最大，最大距离是√2+1，故答案为：√2+1，8．如图，在平面直角坐标系xOy 中，直线AB 经过点A （﹣4，0）、B （0，4），⊙O 的半径为1（O为坐标原点），点P在直线AB上，过点P作⊙O的一条切线PQ，Q为切点，则切线长PQ的最小值为√7．解：连接OP、OQ．∵PQ是⊙O的切线，∴OQ⊥PQ；根据勾股定理知PQ2＝OP2﹣OQ2，∵当PO⊥AB时，线段PQ最短；又∵A（﹣4，0）、B（0，4），∴OA＝OB＝4，∴AB＝4√2∴OP=12AB＝2√2，∴PQ=√7；故答案为：√7．9．如图，已知一次函数y＝kx+b的图象经过点P（3，2），与反比例函数y=2x（x＞0）的图象交于点Q（m，n）．当一次函数y的值随x值的增大而增大时，m的取值范围是1＜m＜3．解：过点P 分别作y 轴与x 轴的垂线，分别交反比例函数图象于A 点和B 点，如图， 把y ＝2代入y =2x 得x ＝1；把x ＝3代入y =2x 得y =23，所以A 点坐标为（1，2），B 点坐标为（3，23）， 因为一次函数y 的值随x 值的增大而增大，所以Q 点只能在A 点与B 点之间，所以m 的取值范围是1＜m ＜3．故答案为1＜m ＜3．10．如图，以扇形OAB 的顶点O 为原点，半径OB 所在的直线为x 轴，建立平面直角坐标系xOy ，点B 的坐标为（2，0），若抛物线y =12x 2+k 与扇形OAB 的边界总有两个公共点，则实数k 的取值范围是 ﹣2＜k ＜12 ．解：由图可知，∠AOB ＝45°，∴直线OA 的解析式为y ＝x ，联立{y =xy =12x 2+k消掉y 得， x 2﹣2x +2k ＝0，第11页（共11页）△＝b 2﹣4ac ＝（﹣2）2﹣4×1×2k ＝0， 即k =12时，抛物线与OA 有一个交点， 此交点的横坐标为1，∵点B 的坐标为（2，0），∴OA ＝2，∴点A 的坐标为（√2，√2），∴交点在线段AO 上；当抛物线经过点B （2，0）时，12×4+k ＝0， 解得k ＝﹣2，∴要使抛物线y =12x 2+k 与扇形OAB 的边界总有两个公共点，实数k 的取值范围是﹣2＜k ＜12．故答案为：﹣2＜k ＜12。
2021甘肃中考115语文 教用配赠-限时训练(七) 仿写、修辞、对联
限时训练(七) 仿写、修辞、对联(时间:30分钟)班级: 姓名:1.请你从下面给出的三个爱国人物中任选一个,按照例句仿写一句话。
杜甫闻一多邓稼先例句:“土地的歌者”艾青,在他深爱着的土地上用嘶哑的喉咙歌唱。
仿句:2.请你仿照示例,写两行小诗。
示例:每一缕晨曦都是喷薄而出的希望3.请仿照画波浪线的句子在横线处补写一个句子。
本次研学,让我的学习通道全部打开了。
我赏红色歌剧,如沐和煦春风,净化了我的审美情趣; , , ;我写红色心得,如经炉火淬炼,坚定了我的红色信仰。
巍巍沂蒙山,铭记了一段可歌可泣的历史,我要不断地留下自己的红色足迹,努力成为新时代的红色沂蒙人。
4.根据语境,仿写画线句子。
优秀的书法作品,如洒落在中华民族历史长河中的珍珠,散发着璀璨而独特的光芒。
颜真卿的楷书(1) ;王羲之的行书(2) ;张旭的草书癫狂恣肆,如暴风骤雨,让猝不及防的人们找不到前进的方向……5.按要求答题。
“每天进步一点点,三年语文灿年华。
”在传统节日,人们会用特定的形式表达纪念和祝福。
请在清明节、端午节和中秋节中任选一个节日,仿照例句再写一个句子例句:春节——无论是放鞭炮,还是贴春联,都传递着对亲人安康的祝福。
6.仿写句子。
若要有明亮的眼睛,请多看到别人的长处;若要有姣好的面容,请多展露真诚的微笑; , ;若要有宽广的胸怀,请多接纳别人的忠言。
7.仿照例句中加点部分,在横线处仿写,使语意承接紧密,和谐一致。
祖国啊,你的荣光,照亮历史的隧洞．．．．．．．．;．．．．．．．,．迎来新世界的黎明你的富饶, , ;你的自由, , ;你的腾飞, , 。
8.学校将五月定为“大阅读”主题月,将开展一系列活动,请你积极参与。
为纪念中华人民共和国成立70周年,班级将举行“我和我的祖国”系列活动,请你根据示例将活动内容补充完整。
“读起来”,;“讲起来”,砥砺强国志向;“”,汇聚报国行动。
9.下列句子中没有使用修辞手法的一项是( )A.微黄的阳光斜射在山腰上,那点薄雪好像忽然害了羞,微微露出点粉色。
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2021中考选择填空满分限时训71．（3分）实数3的相反数是（ ） A ．﹣3 B ．3 C ．−13D ．132．（3分）分式x+5x−2的值是零，则x 的值为（ ）A ．2B ．5C ．﹣2D ．﹣53．（3分）下列多项式中，能运用平方差公式分解因式的是（ ） A ．a 2+b 2B ．2a ﹣b 2C ．a 2﹣b 2D ．﹣a 2﹣b 24．（3分）下列四个图形中，是中心对称图形的是（ ）A ．B ．C ．D ．5．（3分）如图，有一些写有号码的卡片，它们的背面都相同，现将它们背面朝上，从中任意摸出一张，摸到1号卡片的概率是（ ）A ．12B ．13C ．23D ．166．（3分）如图，工人师傅用角尺画出工件边缘AB 的垂线a 和b ，得到a ∥b ．理由是（ ）A ．连结直线外一点与直线上各点的所有线段中，垂线段最短B ．在同一平面内，垂直于同一条直线的两条直线互相平行C ．在同一平面内，过一点有一条而且仅有一条直线垂直于已知直线D ．经过直线外一点，有且只有一条直线与这条直线平行7．（3分）已知点（﹣2，a ）（2，b ）（3，c ）在函数y =kx （k ＞0）的图象上，则下列判断正确的是（ ） A ．a ＜b ＜cB ．b ＜a ＜cC ．a ＜c ＜bD ．c ＜b ＜a8．（3分）如图，⊙O 是等边△ABC 的内切圆，分别切AB ，BC ，AC 于点E ，F ，D ，P 是DF ̂上一点，则∠EPF 的度数是（ ）A ．65°B ．60°C ．58°D ．50°9．（3分）如图，在编写数学谜题时，“□”内要求填写同一个数字，若设“□”内数字为x ．则列出方程正确的是（ ）A ．3×2x +5＝2xB ．3×20x +5＝10x ×2C ．3×20+x +5＝20xD ．3×（20+x ）+5＝10x +210．（3分）如图，四个全等的直角三角形拼成“赵爽弦图”，得到正方形ABCD 与正方形EFGH ．连结EG ，BD 相交于点O 、BD 与HC 相交于点P ．若GO ＝GP ，则S 正方形ABCD S 正方形EFGH的值是（ ）A ．1+√2B ．2+√2C ．5−√2D ．15411．（4分）点P （m ，2）在第二象限内，则m 的值可以是（写出一个即可） ． 12．（4分）数据1，2，4，5，3的中位数是 ．13．（4分）如图为一个长方体，则该几何体主视图的面积为 cm 2．14．（4分）如图，平移图形M，与图形N可以拼成一个平行四边形，则图中α的度数是°．15．（4分）如图是小明画的卡通图形，每个正六边形的边长都相等，相邻两正六边形的边重合，点A，B，C均为正六边形的顶点，AB与地面BC所成的锐角为β．则tanβ的值是．16．（4分）图1是一个闭合时的夹子，图2是该夹子的主视示意图，夹子两边为AC，BD （点A与点B重合），点O是夹子转轴位置，OE⊥AC于点E，OF⊥BD于点F，OE＝OF＝1cm，AC＝BD＝6cm，CE＝DF，CE：AE＝2：3．按图示方式用手指按夹子，夹子两边绕点O转动．（1）当E，F两点的距离最大时，以点A，B，C，D为顶点的四边形的周长是cm．（2）当夹子的开口最大（即点C与点D重合）时，A，B两点的距离为cm．17．（6分）计算：（﹣2020）0+√4−tan45°+|﹣3|．18．（6分）解不等式：5x﹣5＜2（2+x）．参考答案与试题解析1．（3分）实数3的相反数是（ ） A ．﹣3B ．3C ．−13D ．13【分析】直接利用相反数的定义分析得出答案． 【解答】解：实数3的相反数是：﹣3． 故选：A ．【点评】此题主要考查了实数的性质，正确掌握相反数的定义是解题关键． 2．（3分）分式x+5x−2的值是零，则x 的值为（ ）A ．2B ．5C ．﹣2D ．﹣5【分析】利用分式值为零的条件可得x +5＝0，且x ﹣2≠0，再解即可． 【解答】解：由题意得：x +5＝0，且x ﹣2≠0， 解得：x ＝﹣5， 故选：D ．【点评】此题主要考查了分式值为零的条件，关键是掌握分式值为零的条件是分子等于零且分母不等于零．注意：“分母不为零”这个条件不能少． 3．（3分）下列多项式中，能运用平方差公式分解因式的是（ ） A ．a 2+b 2B ．2a ﹣b 2C ．a 2﹣b 2D ．﹣a 2﹣b 2【分析】根据能够运用平方差公式分解因式的多项式必须是二项式，两项都能写成平方的形式，且符号相反进行分析即可．【解答】解：A 、a 2+b 2不能运用平方差公式分解，故此选项错误； B 、2a ﹣b 2不能运用平方差公式分解，故此选项错误； C 、a 2﹣b 2能运用平方差公式分解，故此选项正确； D 、﹣a 2﹣b 2不能运用平方差公式分解，故此选项错误； 故选：C ．【点评】此题考查了平方差公式，熟练掌握平方差公式是解本题的关键． 4．（3分）下列四个图形中，是中心对称图形的是（ ）A ．B ．C ．D ．【分析】根据中心对称图形的概念对各图形分析判断即可得解． 【解答】解：A 、该图形不是中心对称图形，故本选项不合题意； B 、该图形不是中心对称图形，故本选项不合题意； C 、该图形是中心对称图形，故本选项符合题意； D 、该图形不是中心对称图形，故本选项不合题意； 故选：C ．【点评】本题考查了中心对称图形的概念，中心对称图形是要寻找对称中心，旋转180度后两部分重合．5．（3分）如图，有一些写有号码的卡片，它们的背面都相同，现将它们背面朝上，从中任意摸出一张，摸到1号卡片的概率是（ ）A ．12B ．13C ．23D ．16【分析】根据概率公式直接求解即可．【解答】解：∵共有6张卡片，其中写有1号的有3张， ∴从中任意摸出一张，摸到1号卡片的概率是36=12；故选：A ．【点评】此题考查了概率的求法，用到的知识点为：可能性等于所求情况数与总情况数之比．6．（3分）如图，工人师傅用角尺画出工件边缘AB 的垂线a 和b ，得到a ∥b ．理由是（ ）A ．连结直线外一点与直线上各点的所有线段中，垂线段最短B．在同一平面内，垂直于同一条直线的两条直线互相平行C．在同一平面内，过一点有一条而且仅有一条直线垂直于已知直线D．经过直线外一点，有且只有一条直线与这条直线平行【分析】根据垂直于同一条直线的两条直线平行判断即可．【解答】解：由题意a⊥AB，b⊥AB，∴a∥b（垂直于同一条直线的两条直线平行），故选：B．【点评】本题考查平行线的判定，平行公理等知识，解题的关键是理解题意，灵活运用所学知识解决问题．7．（3分）已知点（﹣2，a）（2，b）（3，c）在函数y=kx（k＞0）的图象上，则下列判断正确的是（）A．a＜b＜c B．b＜a＜c C．a＜c＜b D．c＜b＜a【分析】根据反比例函数的性质得到函数y=kx（k＞0）的图象分布在第一、三象限，在每一象限，y随x的增大而减小，则b＞c＞0，a＜0．【解答】解：∵k＞0，∴函数y=kx（k＞0）的图象分布在第一、三象限，在每一象限，y随x的增大而减小，∵﹣2＜0＜2＜3，∴b＞c＞0，a＜0，∴a＜c＜b．故选：C．【点评】本题考查了反比例函数图象上点的坐标特征，熟练掌握反比例函数的性质是解题的关键．8．（3分）如图，⊙O是等边△ABC的内切圆，分别切AB，BC，AC于点E，F，D，P是DF̂上一点，则∠EPF的度数是（）A．65°B．60°C．58°D．50°【分析】如图，连接OE，OF．求出∠EOF的度数即可解决问题．【解答】解：如图，连接OE，OF．∵⊙O是△ABC的内切圆，E，F是切点，∴OE⊥AB，OF⊥BC，∴∠OEB＝∠OFB＝90°，∵△ABC是等边三角形，∴∠B＝60°，∴∠EOF＝120°，∴∠EPF=12∠EOF＝60°，故选：B．【点评】本题考查三角形的内切圆与内心，切线的性质，圆周角定理等知识，解题的关键是熟练掌握基本知识，属于中考常考题型．9．（3分）如图，在编写数学谜题时，“□”内要求填写同一个数字，若设“□”内数字为x．则列出方程正确的是（）A ．3×2x +5＝2xB ．3×20x +5＝10x ×2C ．3×20+x +5＝20xD ．3×（20+x ）+5＝10x +2【分析】直接利用表示十位数的方法进而得出等式即可． 【解答】解：设“□”内数字为x ，根据题意可得： 3×（20+x ）+5＝10x +2． 故选：D ．【点评】此题主要考查了由实际问题抽象出一元一次方程，正确表示十位数是解题关键． 10．（3分）如图，四个全等的直角三角形拼成“赵爽弦图”，得到正方形ABCD 与正方形EFGH ．连结EG ，BD 相交于点O 、BD 与HC 相交于点P ．若GO ＝GP ，则S 正方形ABCD S 正方形EFGH的值是（ ）A ．1+√2B ．2+√2C ．5−√2D ．154【分析】证明△BPG ≌△BCG （ASA ），得出PG ＝CG ．设OG ＝PG ＝CG ＝x ，则EG ＝2x ，FG =√2x ，由勾股定理得出BC 2＝（4+2√2）x 2，则可得出答案． 【解答】解：∵四边形EFGH 为正方形， ∴∠EGH ＝45°，∠FGH ＝90°， ∵OG ＝GP ，∴∠GOP ＝∠OPG ＝67.5°， ∴∠PBG ＝22.5°， 又∵∠DBC ＝45°， ∴∠GBC ＝22.5°，∴∠PBG ＝∠GBC ，∵∠BGP ＝∠BG ＝90°，BG ＝BG ， ∴△BPG ≌△BCG （ASA ）， ∴PG ＝CG ．设OG ＝PG ＝CG ＝x ， ∵O 为EG ，BD 的交点， ∴EG ＝2x ，FG =√2x ，∵四个全等的直角三角形拼成“赵爽弦图”， ∴BF ＝CG ＝x ， ∴BG ＝x +√2x ，∴BC 2＝BG 2+CG 2=x 2(√2+1)2+x 2=(4+2√2)x 2， ∴S 正方形ABCD S 正方形EFGH=(4+2√2)x 22x 2=2+√2．故选：B ．【点评】本题考查了正方形的性质，全等三角形的判定与性质，勾股定理，直角三角形的性质等知识，熟练掌握勾股定理的应用是解题的关键．11．（4分）点P （m ，2）在第二象限内，则m 的值可以是（写出一个即可） ﹣1（答案不唯一）． ．【分析】直接利用第二象限内点的坐标特点得出m 的取值范围，进而得出答案． 【解答】解：∵点P （m ，2）在第二象限内， ∴m ＜0，则m 的值可以是﹣1（答案不唯一）． 故答案为：﹣1（答案不唯一）．【点评】此题主要考查了点的坐标，正确得出m 的取值范围是解题关键． 12．（4分）数据1，2，4，5，3的中位数是 3 ．【分析】先将题目中的数据按照从小到大排列，即可得到这组数据的中位数． 【解答】解：数据1，2，4，5，3按照从小到大排列是1，2，3，4，5， 则这组数据的中位数是3， 故答案为：3．【点评】本题考查中位数，解答本题的关键是明确中位数的含义，会求一组数据的中位数．13．（4分）如图为一个长方体，则该几何体主视图的面积为20cm2．【分析】根据从正面看所得到的图形，即可得出这个几何体的主视图的面积．【解答】解：该几何体的主视图是一个长为4，宽为5的矩形，所以该几何体主视图的面积为20cm2．故答案为：20．【点评】本题考查了三视图的知识，主视图是从物体的正面看得到的视图．14．（4分）如图，平移图形M，与图形N可以拼成一个平行四边形，则图中α的度数是30°．【分析】根据平行四边形的性质解答即可．【解答】解：∵四边形ABCD是平行四边形，∴∠D＝180°﹣∠C＝60°，∴∠α＝180°﹣（540°﹣70°﹣140°﹣180°）＝30°，故答案为：30．【点评】此题考查平行四边形的性质，关键是根据平行四边形的邻角互补解答．15．（4分）如图是小明画的卡通图形，每个正六边形的边长都相等，相邻两正六边形的边重合，点A，B，C均为正六边形的顶点，AB与地面BC所成的锐角为β．则tanβ的值是19√315．【分析】如图，作AT ∥BC ，过点B 作BH ⊥AT 于H ，设正六边形的边长为a ，则正六边形的半径为，边心距=√32a ．求出BH ，AH 即可解决问题．【解答】解：如图，作AT ∥BC ，过点B 作BH ⊥AT 于H ，设正六边形的边长为a ，则正六边形的半径为，边心距=√32a ．观察图象可知：BH =192a ，AH =5√32a ， ∵AT ∥BC ，∴∠BAH ＝β，∴tan β=BH AH =192a 5√32a =19√315． 故答案为19√315．【点评】本题考查解直角三角形的应用，解题的关键是理解题意，学会添加常用辅助线，构造直角三角形解决问题．16．（4分）图1是一个闭合时的夹子，图2是该夹子的主视示意图，夹子两边为AC ，BD（点A 与点B 重合），点O 是夹子转轴位置，OE ⊥AC 于点E ，OF ⊥BD 于点F ，OE ＝OF ＝1cm ，AC ＝BD ＝6cm ，CE ＝DF ，CE ：AE ＝2：3．按图示方式用手指按夹子，夹子两边绕点O 转动．（1）当E ，F 两点的距离最大时，以点A ，B ，C ，D 为顶点的四边形的周长是 16 cm ．（2）当夹子的开口最大（即点C 与点D 重合）时，A ，B 两点的距离为 6013 cm ．【分析】（1）当E ，F 两点的距离最大时，E ，O ，F 共线，此时四边形ABCD 是矩形，求出矩形的长和宽即可解决问题．（2）如图3中，连接EF 交OC 于H ．想办法求出EF ，利用平行线分线段成比例定理即可解决问题．【解答】解：（1）当E ，F 两点的距离最大时，E ，O ，F 共线，此时四边形ABCD 是矩形，∵OE ＝OF ＝1cm ，∴EF ＝2cm ，∴AB ＝CD ＝2cm ，∴此时四边形ABCD 的周长为2+2+6+6＝16（cm ），故答案为16．（2）如图3中，连接EF 交OC 于H ．由题意CE ＝CF =25×6=125（cm ）， ∵OE ＝OF ＝1cm ，∴CO 垂直平分线段EF ，∵OC =√CE 2+OE 2=√(125)2+12=135（cm ），∵12•OE •EC =12•CO •EH ，∴EH =1×125135=1213（cm ）， ∴EF ＝2EH =2413（cm ）∵EF ∥AB ，∴EF AB =CE CB =25， ∴AB =52×2413=6013（cm ）．故答案为6013．【点评】本题考查旋转的性质，矩形的判定和性质，平行线分线段成比例定理等知识，解题的关键是理解题意，灵活运用所学知识解决问题．17．（6分）计算：（﹣2020）0+√4−tan45°+|﹣3|．【分析】利用零次幂的性质、二次根式的性质、特殊角的三角函数值、绝对值的性质进行计算，再算加减即可．【解答】解：原式＝1+2﹣1+3＝5．【点评】此题主要考查了实数运算，关键是掌握零次幂、二次根式的性质、特殊角的三角函数值、绝对值的性质．18．（6分）解不等式：5x ﹣5＜2（2+x ）．【分析】去括号，移项、合并同类项，系数化为1求得即可．【解答】解：5x ﹣5＜2（2+x ），5x ﹣5＜4+2x5x ﹣2x ＜4+5，3x ＜9，x ＜3．【点评】本题考查了解一元一次不等式，熟练掌握解不等式的步骤是解题的关键．。