上海中考易错题整理
上海市九年级初三中考英语-各题型易错题汇总
昂立在线-初三优题库汇总一、语音1.The food my mother cooks is delicious. Which of the following is correct for the underlined word?A) [f ɔ:d ] B) [fu:d ] C) [fud] D) [fɔnd]答案：B解析：双O发长音：food 、cool、room、fool、双O发短音：cook、foot、good、wood、book2.John read the book again in order to get more information from it. Which of the following is correct for the underlined word in the sentence?A. /r i: d/B. /r e d/C. /r e id/D. /r a i d/ 答案：B解析：read在原型是读作/r i: d/，在作为过去式讲的时候读作/r e d/3.Which of the following underlined parts is different in pronunciation from others?A) My office is on the ground floor.B) It was cloudy yesterday afternoon.C) I’d like to buy this pair of tr ousers.D) I’ve been here for a c ouple of days.答案：D解析：A、/graund/ B、/klaudi/ C、/trauzəz/ D、/kʌpl/4.Which of the following underlined parts is different in pronunciation from others?A) Ann survived in the earthquake. B) Would you like some tea?.C) My aunt lives in the east of China. D) There is a picture in my mind.答案：C解析：A、/sə’raiv/ B./laik/ C./liv/ D./maind/5.Which of the following underlined parts is different in pronunciation from others?A. What animal jumps highest?B. Here is an invitation from a club.C. My father is a businessman.D. He found it was a dull party.答案：D解析：A.B.C中的字母U发的都是短元音ʌ，只有D选项当中的字母U 发的是短音i二、单选1. ---How are you going to meet your aunt at the airport _____ Thursday morning?---I’m going there _____ my car.A. on, inB. on, byC. in, byD. in, in答案：A解析：具体某日的早、午、晚要用介词on，by car，by后无冠词或代词，in one’s car，in后有冠词或介词。
2024年上海市英语中考错题整理(1)
上海英语中考错题整理及参考答案(五)一、Choose the best answer.1.The magazine can’t be taken out of the reading room for time being.A.aB.anC. theD. /2.Try to do one thing at time, and do it well.A.aB.anC. theD. /3.Where are two dinner plates in the set? I can only find four.A.otherB. the otherC. anotherD. others4.All the neighbours have pity the poor boy who lives in the garage.A.inB. onC. atD. for5.of these two pairs of trousers looks good on me. Can you show me another pair?A.BothB. AllC. NoneD. Neither6.We questioned two people, but of them was the missing person.A.neitherB. noneC. bothD. all7.People use public transportation if they don’t wear masks or show the QR codes.A.mustn’tB. wouldn’tC. needn’tD. couldn’t8.he finish this task without any help in two days?A.MayB. CanC. Ought toD. Need9.They argued among and finally drew a conclusion.A.themB. theirC. theirsD. themselves10.The bund is always crowded with people the nights of National Day.A.atB. forC. inD. on11.The underground was so crowded that I could find space on it.A.fewB. a fewC. littleD. a little12.The West Belfast School was just a single classroom with only students when it first opened in 1971.A.littleB. fewC. a littleD. a few13.The farmer raised plenty of on his farm to sell for food and money.A.sheepB. cowC. pigD. chicken14.They are eager to know they may keep the book from the new library.A.how longB. how fastC. how soonD. how often15.In the past several months a new munity park and will be open to the public soon,A.is builtB. was builtC. has been builtD. will be built16.Mun was surprised to find her little son all her suitcases already.A.was packing B,.has packed C. had packed D. would pack17.Like all Greeks, she the legend of Odysseus since childhood.A.knowsB. knewC. has knownD. will know18.Johnny with a host family for two years. Now he’s used to the life in America.A.staysB. would stayC. is stayingD. has stayed19.In recent years, natural disasters great damage to many tourist attractions.A.will causeB. have causedC. had causedD. were causing20.Tracy suggested to the countryside to breathe fresh air at weekends.A.to driveB. drivingC. driveD. drives21.The government suggests people the Spring Festival in their working place this year.A.to spendB. spendC. spendingD. will spend22.Tracy saw there a necklace and a pair of earrings in the giftbox.A.isB. wasC. beD. will be23.great fun it is to pay a visit to the Science and Technology Museum at weekends!A.HowB. WhatC. What aD. What an二、plete the sentences with the given words in their proper forms.1. The play got good and quickly became wellknown. ( review )2. His heavy illness caused him to lose his . ( memorize )3. The students felt extremely tired because the lecture was nearly three hours in . ( long )4. When you the way your parents deal with the problem, you can offer yours. ( like )5. We celebrated the birthday of the munist Party of China on July 1, 2021. ( hundred )6. The captured the city of Troy through a trick. ( Greek )三、plete the sentences as required.1.Let’s take a short walk along the road after dinner and enjoy the cool wind. (改为反义疑问句)Let’s take a short walk along the road after dinner and enjoy thecool wind，？2.Jenny hardly has coffee with milk in it. (改为反义疑问句)Jenny hardly has coffee with milk in it，？3.Mr Li is very kind. He has never lost his temper. (改为反义疑问句)Mr Li is very kind. He has never lost his temper，？4.Kitty never reads detective stories before going to bed. (改为反义疑问句)Kitty never reads detective stories before going to bed，？5.Double reduction policy has enabled students to have more time to develop their interest. (改为反义疑问句)Double reduction policy has enabled students to have more time to develop their interest，？6.Linda kept practicing so that she could remember all the lines in the play. (保持句意基本不变)Linda kept practicing to remember all the lines in the play.7.My teacher asked Tim, “ How do you get on with others? ” (保持句意基本不变) My teacher asked Tim he on with others.8.The bus driver should take charge of all the passengers’ safety. (保持句意基本不变)The bus driver should be all the passengers’ safety.9.Jason happened to meet his class teacher when he walked to the park. (保持句意基本不变)Jason happened to meet his class teacher when he walked to the park .e your mind, and you will work out the solution by yourself. (保持句意基本不变)Use your mind, and you will work out the solution by yourself. 11.The big house cost the Smiths one million dollars. (保持句意基本不变)The Smiths the big house one million dollars.12.Tina managed to create her first ic strips without any help. (保持句意基本不变) Tina creating her first ic strips without any help.13.To add variety, some frames in ic strips are left without borders. (对画线部分提问)some frames in ic strips left without borders.14.The children in Tom’s village used to go fishing by the river. (对画线部分提问)the children in Tom’s village used to go fishing?15.“ Don’t forget to close the windows before you leave,” said Mr Thompson to his son. (改为间接引语)Mr Thompson reminded his son to close the window before . 16.“ Have you finished reading the ic strips? ” Lucy asked the students. (改为间接引语)Lucy asked the students they finished reading the ic strips.17.The senior officer said to the soldiers, “Don’t fire without my permission.” (改为间接引语)The senior officer the soldiers to fire without my permission.18.“When will we leave tomorrow morning?” Sophia asked her friends. (改为间接引语)Sophia asked her friends when leave tomorrow morning.19.“ Which country will hold the next Olympic Games? ” My son asked me. (改为间接引语)My son asked me which country the next Olympic Games.20.It should be Tim’s turn to clean the classroom after school today. (对画线部分提问)turn it be to clean the classroom after school today?21.You can press the ESC button to exit the programme. (对画线部分提问)can I press to exit the programme?22.The students at Mayfield School publish the school newspapers once a month. (改为被动语态)The school newspapers once a month by the students at Mayfield School.23.Miss Yang asked Tim, “ Do you plan to go abroad to further your study?” (合并为一句)Miss Yang asked Tim he to go abroad to further your study. 24.Will we have an autumn outing next week？Please tell me. (合并为一句) Please tell me we have an autumn outing next week.上海英语中考错题整理（五）参考答案一、Choose the best answer.15 C A B B D610 A A B D D1115 C D A A C1620 C C D B B2123 B B B二、plete the sentences with the given words in their proper forms.1.reviews2. memory3. length4. dislike5.hundredth6. Greeks三、plete the sentences as required.1. shall we2. does she3. has he4. does she5. hasn’t it6. in order/ so as7. how got8. responsible for9. on foot 10. If you 11. purchased / bought for12. succeeded in 13. Why are 14. Where did15. his left / his leaving 16. if / whether had 17. told/ordered not18. they would 19. would hold 20. Whose to21. Which button 22. are published 23. if planned24. If/whether will。
上海中考英语初三易错题+中考英语易错知识点
上海中考英语初三易错题+中考英语易错知识点上海中考英语初三易错题1.They have given a lot of help to the homeless in the earthquake(改为被动语态)A lot of help______ _______ given to the homeless in the earthquake.2. This grey laptop is as big as that red one.(保持原句意思)This grey laptop is the ______ ______ as the red one.3. It is great fun to ride a horse in the park.(改为感叹句)______ _______ it is to ride a horse in the park!4. Of all the tourist attractions, Martha likes the Great Wall best.(保持句意不变)Martha likes the Great Wall _______ _______any other tourist attraction.5. Gou Yanling from Harbin in China has memorized more than 15,000 telephone numbers.(对划线部分提问)_______ ________ telephone numbers has Gou Yanling from Harbin in China memorized?6.If you think about each picture for 10 to 20 seconds, it will stay in your mind better.(保持句意不变)The picture will ________ stay in your mind better________ you think about it for 10 to 20 seconds.7. We held our school sports meeting in early March.(对划线部分提问)_________ _______ you hold your school sports meeting?8.Jimmy returned the book just now. He borrowed it two weeks ago.(保持句意不变)Jimmy has _______the book ________two weeks.9. There is little snow in Shanghai in winter. (保持原句意思)It _________ _________ in Shanghai in winter.10. Great changes have taken place in my hometown in the past few years.(保持原句意思)_______ have ________ great changes in my hometown in the past few years.11.I was successful in persuading (说服) him to change his mind(保持句意不变)I ________ _________ persuade him to change his mind.12. In winter the ________it snows, the happier the children will feel.A heavyB more heavilyC heavilyD heavier13. More and more foreigners are living and working in Shanghai at present. The underlined part means"_________".A at a timeB at the momentC just nowD from time to time14. Steven usually washes his car _________Sunday mornings.A atB inC onD for15.________wonderful news report they wrote! All of us are proud of them.A What aB WhatC How aD How16. Mum _______me when I was young. She always made me do things carefully.A was angry withB was careful withC was strict withD was satisfied with17.Hans is ________honest. He is often praised by his teachers and friends.A aB anC theD /18. They completed the task successfully ________ a good plan.A forB intoC throughD across19. They have to finish going over their lessons before 9 o'clock,_______?A do theyB don't theyC have theyD haven't they20. I was told to take the pills three at a time every day. The underlined part means ____________.A at onceB at lastC each timeD sometimes21. My aunt's baby was born __________the morning of the National Day.A onB inC atD of22. How much did it cost to build the school?Forty __________yuan.A millionsB millionC millions ofD million of23. Soon you __________a senior high school student. Isn't it exciting?A becomeB will becomeC becameD have become24. Could you tell me ____________?A when did the accident happenB how long you had been hereC what causes global warmingD that you will come tomorrow25. We should __________consumers' suggestions. The underlined word means _______.A agreeB affordC argueD accept26.With more private cars, people find ________difficult to get rid of traffic jams during rush hours.A itB thisC thatD those27. There is somebody at the door. ________I go and see who it is?A ShallB MustC WillD Would28.Mr Wang asked ______________.A that he could open the doorB it could he open the doorC how could he open the doorD how he could open the door29.I have got two tickets _________Jolin's concert tonight.Would you like to go there with me?A toB withC ofD for30. The child isn't able to remember these difficult words.__________ he has already tried hard.A whenB ifC thoughD because31.The students in our school should __________ our School Culture Festival from now on.A get on withB get rid ofC get tired ofD get ready for32. It's __________pleasure for me to be invited to play the piano at the concert.A aB anC theD /33. The twins are so much alike that it is difficult to tell one from _________.A otherB the otherC othersD another34. I ____________do e-shopping at home than go to the department store.A would ratherB would likeC had betterD prefer35. I'll _________photo taking after I retire. I think it is a good hobby.A take awayB take offC take outD take up36. Water is much more precious than electricity, for the water for drinking is ____________.A disappointedB limitedC terribleD various38. ____________singer over there is very popular. She has lots of fans from home and abroad.A AB AnC TheD /39. Believe me, you should follow Tom as what he said is based __________facts.A inB withC byD on40. We have to wait for the next bus because there isn't any room left in this one. The underlined part means"_____________"A houseB spaceC areaD chair41. Nowadays people can get _________on everything by surfing the internet.A importanceB knowledgeC newsD idea42.Soon we will graduate from junior high school._________time flies!A whatB HowC what aD what an43. John can ___________why the weather is getting warmer and warmer. He is an expert on climate.A excuseB explainC exchangeD examine44. Jack has made up his mind to live in the country. The underlined part means"____________".A agreedB promisedC decidedD hesitated45. I ___________ my bicycle to Ben this morning. He has not returned it yet.A borrowedB lentC keptD showed46.Sorry for keeping you waiting for me so long._____________.A Don't mention itB All rightC That's okD Not at all.47. Try your best, ________you will make great progress in your study.A but C if C or D and48. Brian _________many famous places since he came to live in Shanghai last year.A has visitedB will visitC was visitingD had visited49. I'm sorry I didn't hear what you _____________.Could you repeat it?A talkedB toldC saidD spoke50.I think I will ________ fishing as a hobby after I retire in a few years.A take upB take offC take outD take away51. Jane Austin wrote a lot of books but I've only read __________ of them.A littleB a littleC fewD a few52. Every student likes Miss Green because she always talk to them _______.A politelyB lovelyC friendlyD luckily53.It's better to teach a man to fish than ________him fish.A givingB to giveC givesD gaveGive a man a fish and you feed him for a day. Teach a man to fish and you feed him for a lifetime.54.Nowadays people usually get ________information from TV, newspaper and the Internet.A quiet a fewB a number ofC a lot ofD a pair of55. People think plants have _________longest life of all things on the earth.A /B anC aD the56.__________computers have become smaller and smaller.A At that timeB Right thenC Since thenD At a time57.This ruler isn't very long. She wants a ___________one.A longB shortC shorterD longer58. The price of vegetables is very high at present. The underlined part means:"____________"A for the time beingB at a timeC since thenD right away59.I don't think this is a good idea. Have you got any ________suggestions?A anotherB the otherC othersD other60.________exciting the opening ceremony(仪式) of the 10th Guangzhou Asian Games was!A What anB What aC WhatD How61. Eric completed the science test_________in our class.A more quicklyB most quicklyC the quickestD quicker62.Till now, Doris ________Pudong for more than 10 years.A has been inB has been toC comes toD came to63.Could you tell me __________?A Where is the school libraryB Who's on dutyC Whose book is thisD What are they doing64. In front of our school, there is ________one-way street.A anB aC /D the65.Kate and her sister went to holiday with a cousin of ________.A theirB theirsC herD hers66.Professor Yi Zhongtian's talk __________just now. You can borrow the tape if you want.A is recordedB will be recordedC was recordedD recorded67.The doctor ordered the patient to _______all food for at least twenty-four hours.A take offB keep offC show offD turn off68.We should give a hand to ________blind when they need any help in life.A aB anC theD /69. Railway High-speed (高速列车) can run _________than ordinary trains.A much more quicklyB much quickC much quicklyD much quicker70.Our teacher has just gone to the library. I'm not sure ________he will come back.A how longB how oftenC how fastD how soon71. The plane to London will arrive_________one o'clock this afternoon.A inB untilC sinceD after72.Please help__________to cook some chicken, Jack.Our guests are coming soon.A yourselfB youC meD yourselves73.The girl is too short to reach_________the book_________the dictionary on the shelf.A both...andB neither...norC not...butD either...or74.I'm glad you've come back from Beijing. Please tell me how long you __________there.A have stayedB had stayedC have been stayingD stayed75._________fat sheep! Who's taking care of them?A HowB WhatC What aD How a76.We will make laws __________our environment.A to protectB protectC protectingD protected77.They had a pleasant chat ____________a cup of coffee.A forB withC duringD over78.Mr Brown is an experienced teacher and he will teach_______English this term. A your B yours C yourselves D you79. Would you like some tea or coffee?__________.A Yes, I'd love to.B No, thanks.C Tea, pleaseD All of them.80.Tony's English class is really interesting. We all like _____.(he)81.With the _____________of the new techonology, these computers become popular.(develop)82.Tom has great __________in collecting stamps and travelling around the world.(interesting)83.Never give up trying, and ___________will come to you in the end.(succeed)84.Tomorrow will be my grandma's ______________birthday.(ninety)85.Humans have five ______________: sight,hearing,taste,smell and touch.(sense)86.This building was_________the History Museum of the State.(one)87.A lot of fish __________when the lake is polluted. (appear)88. If you want to _________in the future, you must work hard from now on.(success)89.He thought it was a great ___________to meet the famous film star.(please)90.I was sure of the number of death as I got it from the _________website(office)91.The Water Cube, which uses rain to wash _________, can also recycle water(it)92.That road is much________, I know, We'd better drive our van.(widely)93. How did Phelps become so good? He was born with the body of a _________(swim)94.We lay on the floor just for a rest. (改为一般疑问句)________you __________on the floor just for a rest?95. The learned man wondered ________electricity was in some way like lightening during a thunderstorm.A whatB howC thatD whether96.In some states of America, children must stay in school until they are sixteen.(句意不变)In some states of America, children ________ __________ school until they are sixteen.97. She visited the factory _________we visited last week.A thatB whereC whichD in which98.We visited the factory___________she worked.A whichB whereC that D. how99.. Mom,can you tell me where the park is?If you set out by bike__________Shanghai Road, you can see it.A fromB toC downD at100.I took one-third of the cake. The rest ______to my brother.A leftB was leftC were leftD had left101. ________ her great joy, her daughter was finally saved by the doctors.A) In B) To C) At D) For1.has been2. same size3. What fun4.better than5. How many6. not unless7. when did 8. Kept for 9.hardly/seldom snows 10.There been 11. Managed to 12.B 13.B 14.C 15.A 16.C 17.D 18.C 19.B 20.C 21.A 22. B 23. B 24. C 25.D 26.A 27.A 28.D 29.D 30.C 31. D 32.A 33. B 34. A 35. D 36. B 37.C 38.C 39.D 40.B 41.B 42.B (How fast time flies!) 43.B 44.C 45.B 46.C 47.D 48.A 49.C 50.A 51.D 52.A 53.B 54.C 55. D 56.C 57.D 58.A 59.D 60.D 61.B 62.A 63.B 64.B 65.B 66.C 67.B 68.C 69.A 70.D 71.D 72.C 73.D 74.A 75.B 76.A 77.D 78.D 79.C 80.him 81.development 82.interest 83.success 84.ninetieth 85.senses86.once87.disappear 88.succeed 89.pleasure 90.official 91.itself 92.wider 93.swimmer 94.did lie 提示lie 不及物动词lay 及物动词lie 两个意思撒谎(lied lied lying) 躺，位于,在于(lay lain lying )lay 下（蛋），放置（sth）(laid laid laying)95.D那个有学识的人怀疑闪电是在暴风雨中电所呈现出的另一种形式.96. mustn’t leave 97.A 98.B 99.C100. 指代不可数名词或者一件物品的一部分时要用单数。
上海初三英语易错题汇编
上海初三英语易错题汇编初三易错题【主要考点】不定代词★1. I will never know what was on his mind at the time,nor will ____ .A. anyoneB. anyone elseC.no oneD. no one else 【正确答案】B【解析】根据句意，表示“其他人也是”【主要考点】关系词★★2.You should treat him the way ____ suits him most .A.thatB.in whichC.of whichD./【正确答案】that【解析】先行词为“the way”【主要考点】副词★★3.What do you think of the concert?I really enjoy it.I didn't expect it was ____ wonderful.A.asB.moreC.mostD.very【正确答案】A【解析】省略句，as I had thought【主要考点】句转★★4.My little son weighed 30 kilograms at the age of 10.(对划线部分提问）How _____ ______ your little son weigh at the age of 10?【正确答案】much did,【解析】英语中对重量提问可以用how much.【主要考点】固定句型★★5.She had no choice but ____________to sleep.A.goB.to goC. goingD. gone【正确答案】B【解析】have no choice but to do 别无选择只能做某事；可以记一句口诀：有do无to, 有to 无do.【主要考点】词转★★★6.I knocked on the door but there was no__________. (responsibility)【正确答案】response【解析】此处缺名词，且意义应为“回应；回答”，故填response。
上海中考易错题分类汇编
易错题分类汇编一、数与式（A ）2 （B（C ）2± （D）例题：等式成立的是．（A ）1c ab abc =（B ）632x x x =（C ）112112a a a a ++=--（D ）22a x a bx b =． 二、方程与不等式 ⑴字母系数例题：关于x 的方程2(2)2(1)10k x k x k ---++=，且3k ≤．求证：方程总有实数根． 例题：不等式组2,.x x a >-⎧⎨>⎩的解集是x a >，则a 的取值范围是． （A ）2a <-，（B ）2a =-，（C ）2a >-，（D ）2a ≥-．⑵判别式例题：已知一元二次方程222310x x m -+-=有两个实数根1x ，2x ，且满足不等式121214x x x x <+-，求实数的范围． ⑶解的定义例题：已知实数a 、b 满足条件2720a a -+=，2720b b -+=，则ab ba+=____________． ⑷增根例题：m 为何值时，22111x m xx x x --=+--无实数解． ⑸应用背景例题：某人乘船由A 地顺流而下到B 地，然后又逆流而上到C 地，共乘船3小时，已知船在静水中的速度为8千米/时，水流速度为2千米/时，若A 、C 两地间距离为2千米，求A 、B 两地间的距离． ⑹失根例题：解方程(1)1x x x -=-． 三、函数 ⑴自变量例题：函数y =中，自变量x 的取值范围是_______________．⑵字母系数例题：若二次函数2232y mx x m m =-+-的图像过原点，则m =______________．⑶函数图像例题：如果一次函数y kx b =+的自变量的取值范围是26x -≤≤，相应的函数值的范围是119y -≤≤，求此函数解析式．⑷应用背景例题：某旅社有100张床位，每床每晚收费10元时，客床可全部租出．若每床每晚收费再提高2元，则再减少10张床位租出．以每次这种提高2元的方法变化下去，为了投资少而获利大，每床每晚应提高_________元．四、直线型 ⑴指代不明例题：直角三角形的两条边长分别为，则斜边上的高等于________．⑵相似三角形对应性问题例题：在ABC △中，9AB =，12AC =18BC =，D 为AC 上一点，:2:3DC AC =，在AB 上取点E ，得到ADE △，若两个三角形相似，求DE 的长．⑶等腰三角形底边问题例题：等腰三角形的一条边为4，周长为10，则它的面积为________． ⑷三角形高的问题例题：等腰三角形的一边长为10，面积为25，则该三角形的顶角等于多少度？⑸矩形问题例题：有一块三角形ABC 铁片，已知最长边BC =12cm ，高AD =8cm ，要把它加工成一个矩形铁片，使矩形的一边在BC 上，其余两个顶点分别在三角形另外两条边上，且矩形的长是宽的2倍，求加工成的铁片面积？⑹比例问题 例题：若b c c a a bk a b c+++===，则k =________． 五、圆中易错问题⑴点与弦的位置关系例题：已知AB 是⊙O 的直径，点C 在⊙O 上，过点C 引直径AB 的垂线，垂足为点D ，点D 分这条直径成2:3两部分，如果⊙O 的半径等于5，那么BC = ________．⑵点与弧的位置关系例题：PA 、PB 是⊙O 的切线，A 、B 是切点，78APB ∠=︒，点C 是上异于A 、B 的任意一点，那么ACB ∠= ________．⑶平行弦与圆心的位置关系例题： 半径为5cm 的圆内有两条平行弦，长度分别为6cm 和8cm ，则这两条弦的距离等于________．⑷相交弦与圆心的位置关系例题：两相交圆的公共弦长为6，两圆的半径分别为5，则这两圆的圆心距等于________．⑸相切圆的位置关系 例题：若两同心圆的半径分别为2和8，第三个圆分别与两圆相切，则这个圆的半径为________．一，常见易错题1．一个数的绝对值是5，则这个数是_________；__________数的绝对值是它本身． 2．_________的倒数是它本身；_________的立方是它本身．3．关于x 的不等式40x a -≤的正整数解是1和2；则a 的取值范围是_________． 4．不等式组213,.x x a ->⎧⎨>⎩的解集是2x >，则a 的取值范围是_________．5．若()2211a a a +--=，则a =_________．6．当m 为何值时，函数21(3)45m y m x x +=++-是一个一次函数．7．若一个三角形的三边都是方程212320x x -+=的解，则此三角形的周长是_________．8．若实数a 、b 满足221a a =+，221b b =+，则a b +=________．9．在平面上任意画四个点，那么这四个点一共可以确定_______条直线． 10．已知线段AB =7cm ，在直线AB 上画线段BC =3cm ，则线段AC =_____．11．一个角的两边和另一个角的两边互相垂直，且其中一个角是另一个角的两倍少30︒，求这两个角为12．三条直线公路相互交叉成一个三角形，现在要建一个货物中转站，要求它到三条公路的距离相等，则可供选择的地址有_______处？13．等腰三角形一腰上的高与腰长之比为1:2，则该三角形的顶角为_____．14．等腰三角形的腰长为a ，一腰上的高与另一腰的夹角为30︒，则此等腰三角形底边上的高为_______．15．矩形ABCD 的对角线交于点O ．一条边长为1，OAB △是正三角形，则这个矩形的周长为______．16．梯形ABCD 中，AD BC ∥，90A ∠=︒，AB =7cm ，BC =3cm ，试在AB 边上确定P 的位置，使得以P 、A 、D 为顶点的三角形与以P 、B 、C 为顶点的三角形相似．17．已知线段AB =10cm ，端点A 、B 到直线l 的距离分别为6cm 和4cm ，则符合条件的直线有___条．18．过直线l 外的两点A 、B ，且圆心在直线l 的上圆共有_____个．19．在Rt ABC △中，90C ∠=︒，3AC =，5AB =，以C 为圆心，以r 为半径的圆，与斜边AB 只有一个交点，求r 的取值范围．20．直角坐标系中，已知(1,1)P ，在x 轴上找点A ，使AOP △为等腰三角形，这样的点P 共有多少个？21．在同圆中，一条弦所对的圆周角的关系是______________．22．圆的半径为5cm ，两条平行弦的长分别为8cm 和6cm ，则两平行弦间的距离为 _______。
上海中考数学复习一元二次方程组专项易错题
上海中考数学复习一元二次方程组专项易错题一、一元二次方程1．解方程：（2x+1）2=2x+1． 【答案】x=0或x=12-. 【解析】试题分析：根据因式分解法解一元二次方程的解法，直接先移项，再利用ab=0的关系求解方程即可.试题解析：∵（2x+1）2﹣（2x+1）=0， ∴（2x+1）（2x+1﹣1）=0，即2x （2x+1）=0， 则x=0或2x+1=0， 解得：x=0或x=﹣12．2．解方程：x 2－2x ＝2x ＋1.【答案】x 1＝2，x 2＝2 【解析】试题分析：根据方程，求出系数a 、b 、c ，然后求一元二次方程的根的判别式，最后根据求根公式x =求解即可.试题解析：方程化为x 2－4x －1＝0. ∵b 2－4ac ＝(－4)2－4×1×(－1)＝20，∴x ＝42±＝， ∴x1＝2，x 2＝23．已知关于x 的一元二次方程x 2﹣x+a ﹣1=0． （1）当a=﹣11时，解这个方程；（2）若这个方程有两个实数根x 1，x 2，求a 的取值范围；（3）若方程两个实数根x 1，x 2满足[2+x 1（1﹣x 1）][2+x 2（1﹣x 2）]=9，求a 的值． 【答案】（1）123,4x x =-=（2）54a ≤（3）-4 【解析】分析：（1）根据一元二次方程的解法即可求出答案； （2）根据判别式即可求出a 的范围； （3）根据根与系数的关系即可求出答案．详解：（1）把a =﹣11代入方程，得x 2﹣x ﹣12=0，（x +3）（x ﹣4）=0，x +3=0或x ﹣4=0，∴x 1=﹣3，x 2=4；（2）∵方程有两个实数根12x x ，，∴△≥0，即（﹣1）2﹣4×1×（a ﹣1）≥0，解得54a ≤：； （3）∵12x x ，是方程的两个实数根，222211221122101011x x a x x a x x a x x a -+-=-+-=∴-=--=-，，，．∵[2+x 1（1﹣x 1）][2+x 2（1﹣x 2）]=9，∴221122229x x x x ⎡⎤⎡⎤+-+-=⎣⎦⎣⎦，把22112211x x a x x a -=--=-， 代入，得：[2+a ﹣1][2+a ﹣1]=9，即（1+a ）2=9，解得：a =﹣4，a =2（舍去），所以a 的值为﹣4．点睛：本题考查了一元二次方程，解题的关键是熟练运用判别式以及根与系数的关系．4．小王经营的网店专门销售某种品牌的一种保温杯，成本为30元/只，每天销售量y （只）与销售单价x （元）之间的关系式为y ＝﹣10x+700（40≤x≤55），求当销售单价为多少元时，每天获得的利润最大？最大利润是多少元？【答案】当销售单价为50元时，每天获得的利润最大，利润的最大值为4000元 【解析】 【分析】表示出一件的利润为（x ﹣30）,根据总利润=单件利润乘以销售数量,整理成顶点式即可解题. 【详解】设每天获得的利润为w 元，根据题意得：w ＝（x ﹣30）y ＝（x ﹣30）（﹣10x+700）＝﹣10x 2+1000x ﹣21000＝﹣10（x ﹣50）2+4000． ∵a ＝﹣10＜0，∴当x ＝50时，w 取最大值，最大值为4000．答：当销售单价为50元时，每天获得的利润最大，利润的最大值为4000元． 【点睛】本题考查了一元二次函数的实际应用,中等难度,熟悉函数的性质是解题关键.5．已知两条线段长分别是一元二次方程28120x x -+=的两根， （1）解方程求两条线段的长。
上海中考物理易错题整理
（A ） 易错题整理1．蜡烛放在凸透镜的主光轴上，在另一侧距透镜28厘米的光屏上，呈现一个放大清晰的像，则透镜的焦距可能是（ ）A ．40厘米B ．30厘米C ．20厘米D ．10厘米2．甲、乙、丙三个实心正方体放在水平地面上，它们对地面的压强关系是P 甲﹥P 乙﹥P 丙 。
若在三个正方体的上部，沿水平方向分别截去相同高度后，剩余部分对水平地面的压强关系是P 甲=P 乙=P 丙，则三个实心正方体的密度大小关系是 （ ）A ．ρ甲﹥ρ乙﹥ρ丙B ．ρ乙﹥ρ甲﹥ρ丙C ．ρ丙﹥ρ乙﹥ρ甲D ．ρ甲﹥ρ丙﹥ρ乙3．在如图2所示的电路中，电源电压保持不变。
当电键S 闭合后，电路正常工作，一会儿后灯L 熄灭，电压表V 的示数发生变化。
若电路故障只发生在电阻R 或小灯L 上，则故障是 （ ）A ．当电压表V 的示数变大时，一定是小灯L 断路B ．当电压表V 的示数变大时，一定是电阻R 断路C ．当电压表V 的示数变小时，一定是小灯L 短路D ．当电压表V 的示数变小时，一定是电阻R 短路4．在如图6所示的电路中，电源电压和小灯泡的电阻都保持不变。
闭合电键S ，当滑动变阻器的滑片P 向右移动时，小灯泡的发光程度将_______（选填“变亮”、“不变”或“变暗”）；电压表V 的示数与电流表A 的示数的比值将______（选填“变大”、“不变”或“变小”）。
5．小海同学在“测定小灯泡功率”的实验中，电源电压6伏且保持不变，滑动变阻器上标有“20Ω 2A ”的字样，所用小灯泡的额定电压为3.8伏，额定功率在1.5瓦以内。
他电路连接正确，实验步骤正确。
（1）请在图13（A ）中的圆圈内填上适当的电表符号。
（2）当滑动变阻器的滑片P 移在b 端时，他闭合电键S ，发现电流表示数为0.18安，但电压表无示数，把电压表换一个量程，仍无示数，出现这种现象的原因可能是。
该同学经过思考、分析后，重新进行实验，移动滑片P ，当小灯泡正常发光时，电流表示数如图13（B ）所示，则小灯的额定功率为_______瓦。
上海中考数学易错题整理
CEBFDA第8题2011年数学模拟卷一、选择题1．数轴上任意一点所表示的数一定是（ ） A ．整数 B ．有理数 C ．无理数D ．实数2．一次函数32y x =-+的图像一定不经过（ ）A ．第一象限；B ．第二象限；C ．第三象限；D ．第四象限． 二、填空题1．将二次函数y=2（x ﹣1）2﹣3的图象沿着y 轴向上平移3个单位，那么平移后的二次函数图象的顶点坐标是 _________ ．2．经过测量，不挂重物时弹簧长度为6厘米，挂上2.5千克的重物时弹簧长度为7.5厘米，那么弹簧长度y （厘米）与所挂重物的质量x （千克）的函数解析式为 _________ ．3．布袋中有除颜色以外完全相同的8个球，3个黄球，5个白球，从布袋中随机摸出一个球是白球的概率为 ．4. 将二元二次方程0562=+-x xy x 化为二个一次方程为 ． 5．在△ABC 中，点D 在边BC 上，BD =2CD ，b AC a AB ==,，那么=AD ． 6．已知⊙1O 与⊙2O 两圆内含，321=O O ，⊙1O 的半径为5，那么⊙2O 的半径r 的取值范围是 ．7．在△ABC 中，∠C=90°，AC=4，BC=2，△ABC 绕着点C 旋转后, 点B 落在AC 边上的点B ’，点A 落在点A ’，那么tan ∠AA’B’的值为 ．8、 如图，将矩形纸片ABCD(AD>DC)的一角沿着过点D 的直线折 叠， 使点A 与BC 边上的点E 重合，折痕交AB 于点F.若BE:EC=m:n ，则AF:FB= . 9．已知：如图，在Rt△ABC 中，∠C=90°，AC=BC ，AB=6．如果将△ABC 在直线AB 上平行移动2个单位后得△A′B′C′，那么△CA′B 的面积为 _________ ．10．如图，在等边△ABC 中，9A C =，点O 在A C 上，且3A O =，点P 是A B 上一动点，连结O P ，将线段O P 绕点O 逆时针旋转60得到线段O D ．要使点D 恰好落在B C 上，则A P 的长是 ．11．已知A 是平面直角坐标系内一点，先把点A 向上平移3个单位得到点B ，再把点A 绕点B 顺时针方向旋转90°得到点C ，若点C 关于y 轴的对称点为（1,2），那么点A 的坐标是 ．第9题13．把抛物线x x y 22-=向左平移一个单位，所得抛物线的表达式为： ． 三、解答题23．（每小题6分，满分12分）已知：如图，在直角梯形ABCD 中，AD ∥BC ，AB ⊥AD ，BC=CD ，BE ⊥CD ，垂足为点E ，点F 在BD 上，连接AF 、EF ． （1）求证：AD=ED ；（2）如果AF ∥CD ，求证：四边形ADEF 是菱形． 证明：（1）∵BC=CD ∴∠CDB=∠CBD∵AD ∥BC ∴∠ADB=∠CBD ∴∠ADB=∠CDB ，又∵AB ⊥AD ，BE ⊥CD ∴∠BAD=∠BED=90°， ∴在△ABD 和△EBD 中 ∵∠ADB=∠CDB ，∠BAD=∠BED ，BD=BD ， ∴△ABD ≌△EBD ∴AD=ED ．( 2 )23．（本题满分12分，第（1）题7分，第（2）题5分）如图，在⊙O 中，直径AB 与弦CD 垂直，垂足为E ，连接AC ，将△ACE 沿AC 翻折得到△ACF ，直线FC 与直线AB 相交于点G ． （1）证明：直线FC 与⊙O 相切；（2）若BG OB =，求证：四边形OCBD 是菱形． ．解：（1）连接O C ．∵O A O C = ∴12∠=∠由翻折得，△AFC ≌△AEC∴13∠=∠，90F AEC ∠=∠=︒ ∴23∠=∠． ∴OC ∥AF ∴90O C G F ∠=∠=︒ ∵点C 在圆上 ∴直线FC 与⊙O 相切 （2）23．（本题满分12分，第（1）小题满分6分，第（2）小题满分6分）已知：如图，在□ABCD 中，点E 、F 分别是AB 、CD 的中点，CE 、AF 与对角线BD 分别相交于点G 、H ．（1） 求证：DH=HG=BG ；（2） 如果AD ⊥BD ，求证：四边形EGFH23、(本题12分)如图，在平面直角坐标系中，等腰梯形OABC ，CB//OA ，且点A 在x 轴正半轴上.已知C(2，4)，BC= 4.(1)求过O 、C 、B 三点的抛物线解析式，并写出顶点坐标和对称轴；(2)经过O 、C 、B 三点的抛物线上是否存在P 点(与原点O 不重合)，使得P 点到两坐标轴的距离相等.如果存在，求出P 点坐标；如果不存在，请说明理由. 解：(1) ∵C(2,4), BC=4 且 BC//OA ∴ B(6,4)设抛物线为bx ax y +=2()0≠a 将C(2,4),B(6,4)代入得： ∴x x y 38312+-=∴顶点)316,4( 对称轴：直线4=x（第23题图）。
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1.纯净物的化学式是经实验测定得出的。
同学们设计以下甲、乙两组实验方案测定水的组成。
2.①甲方案中发生反应的化学方程式为（14），b端的气体是（15）。
由产生气体的体积可推算出氢气与氧气的质量比为1：8，若氢、氧元素的相对原子质量分别为m和n，则水中氢、氧元素的原子个数比为（16）（用“m”或“n”表示）。
3.②乙方案的实验过程中，B装置中可观察到（17）。
若反应结束测得B装置减轻，则C装置增重的质量会（18） (填“大于”、“等于”或“小于”)。
4.甲、乙方案的反应原理虽不同，但实验的设计依据都是（19）。
5.鉴别物质时通常先用物理方法，后用化学方法．现需鉴别三包失去标签的白色固体粉末，它们可能是CaCO3、Na2CO3和Na2SO4，请按下表完成实验设计实验步骤实验现象和结论步骤一：____________（物理方法）3.工业生产的氢氧化钠常含有碳酸钠杂质。
为测定某样品中氢氧化钠纯度，设计以下实验。
（装置气密性良好，每一步骤反应完全，浓H 2SO 4具有吸水性） 【实验设计】【实验过程】（1）打开弹簧夹a ，先对装置A 、B 、C （已连接）通入空气一会儿，以排尽装置含有的 ，再关闭弹簧夹a ，接上装置D 和E ，打开弹簧夹c ，把硫酸滴入样品中。
（2）反应结束后，待装置冷却后直接称量装置 （填字母序号）。
根据该装置在反应前后的质量差得到CO 2的质量，由此计算出该样品中碳酸钠的质量，最后得到样品中氢氧化钠纯度。
【数据分析】最后计算得到样品中氢氧化钠纯度比实际数据偏大，反思整个实验过程，造成误差可能的原因 。
步骤二： （化学方法） ____________4.酒精（C2H6O）属于（）A.混合物B.氧化物C.单质D.有机物5.互为同素异形体的一组物质是（）A.金刚石和石墨B.双氧水和水C.干冰和冰D.氧气和液氧6.已知某混合溶液由HCl、K2CO3、H2SO4、CuCl2溶液中的两种混合而成，向该溶液中加入Ba(OH)2溶液，产生的沉淀与加入Ba(OH)2溶液的关系如下图。
则混合溶液中溶质的组成为。
7.8.向HCl与Na2SO4混合溶液中加入Ba（OH）2溶液至过量，该过程的现象是。
8.现有盐酸和CaCl2的混合溶液，向其中逐滴加入过量某物质X，溶液的pH 随滴入X的量的变化关系如图所示．则X是（）A．水B．澄清石灰水C．纯碱溶液D．稀盐酸yB CA X根据上述实验，另一同学又绘制了如图2所示的图像，记录滴入X溶液质量与有关量的变化关系如图所示。
回答下列问题：A.图中纵坐标（y）表示的质量。
B.OA段发生反应的化学方程式是。
OC段的现象是C.反应进行到B点时，溶液中的溶质是。
点溶液的PH为。
9.质量均为x克的Mg和Fe，分别与100克浓度为%的稀硫酸反应，生成气体的质量随反应时间的变化如图所示，则：Mg消耗稀硫酸的质量之比为。
H2消耗Mg和Fe的质量之比为。
Fex的取值范围。
反应时间/s 10.实验室检验经检验处理后的水中还存在氯化钠和碳酸钠的实验流程如图：①试剂A的化学式是，试剂A加入过量的作用是；滤液C的溶质的成分。
②写出步骤Ⅱ所发生反应的化学方程式；如果步骤Ⅰ先加入试剂B，步骤Ⅱ加入过量试剂A，也能达到检验氯化钠的目的，理由是。
11.草酸在一定条件下受热分解，生成二氧化碳、一氧化碳和水．某同学为验证草酸分解产物，将一定量的草酸完全分解，并将产物全部通入下列装置．①A 装置U 型管内的物质左侧由白色变蓝色，右侧仍为白色，请写出A 中发生反应的化学方程式 ．②实验中观察到B 、E 中石灰水变浑浊，C 中石灰水不变浑浊，说明草酸分解的产物中有 ，还能观察到的现象是 ．③该装置的不足之处是 ．④为计算草酸分解生成的一氧化碳的质量，某同学在上述实验中测定了如下数据．装置（含其中药品）反应前的质量反应后的质量装置Bm 1m 2装置D（玻璃管及其中氧化铜）n 1n 2 根据上述数据能否计算草酸分解产生的一氧化碳的质量若能，请写出计算式 ；若不能，你认为需要测定的数据是 ．（装置中残留的气体忽略不计）12.有一包白色粉末样品中，可能含有NaCl、CaCO3、K2CO3、Ca（NO3）2、无水CuSO4、Na2SO4 中的一种或几种．现进行以下实验操作：（1）将样品放入水中，粉末全部溶解，得到无色溶液．（2）在上述溶液中滴加BaCl2溶液，有白色沉淀．（3）将上述混合物过滤，在白色沉淀中加入足量的稀盐酸，沉淀部分溶解，且产生无色气体；在滤液中加入AgNO3溶液和稀硝酸，生成白色沉淀．则样品中一定存在的物质是，一定不存在的物质是，可能存在的物质是．13.体X和固体Y的反应可在如图所示的装置中进行．①若X 、Y 均为纯净物，请根据实验现象完成相关分析．现象分析仪器A仪器B黑色固体变成光亮红色石灰水变浑浊B 中发生反应的化学方式是白色固体变蓝色X 是 Y 是②若Y 是纯净物，X 是由两种物质组成的混合物且含有三种元素，A 中黑色固体逐渐减少，B 中澄清石灰水变浑浊，则X 可能的组成是 ．14.某白色固体可能含有Na2SO4、NaCl 、KNO3、K2CO3中的一种或几种．对该固体进行如下实验，下列说法正确的是（ ）A ．取少量固体做焰色反应实验，若看到黄色火焰，证明原固体中含有KNO3B ．M 是BaSO4和BaCO3，N 是AgCl ，原固体中一定含有NaCl 、Na2SO4和K2CO3C ．X 是AgNO3，Y 是BaCl2，原固体中一定含有NaCl 和Na2SO4D．X是Ba（NO3）2，Y是AgNO3，原固体中一定含有NaCl和Na2SO4，可能有KNO315.高温加热碳和氧化铜的混合物，恰好完全反应生成铜和二氧化碳，下列有关物质的质量与反应时间的关系中正确的是（）A． B．C． D．16.图1是甲、乙、丙三种固体物质的溶解的溶解度曲线．根据图1、图2回答：（1）由三种物质的溶解度曲线可判断，甲、乙、丙均属于______（填“易溶”或“能溶”）物质．（2）图2中，试管里预先装有少量生石灰，当往试管中加入适量水时，反应放出的热量使烧杯中某饱和溶液析出固体（不考虑水分蒸发）．请判断：该饱和溶液中溶质是______（填甲或乙或丙）．17.某纯碱样品中含有少量氯化钠，现欲测定其碳酸钠的质量分数，进行如下实验：【实验原理】Na2CO3+H2SO4===Na2SO4 + H2O + CO2↑通过实验测定反应产生的二氧化碳的质量，即可求得原样品中碳酸钠的质量，进而求得碳酸钠在样品中的质量分数。
【实验装置】【实验步骤】①如图连接装置（除B、C外）并加入所需药品。
②称量并记录的质量（m1）。
（称量时注意封闭B的两端。
）⑧按动鼓气球，持续约1分钟。
④连接上B、C。
⑤打开分液漏斗F的活塞，将稀硫酸快速加入D中后，关闭活塞。
⑥按动鼓气球，持续约1分钟。
⑦称量并记录的质量（m2）。
（称量时注意封闭B的两端及E右端的出口。
）⑧计算。
⑴已知碱石灰的主要成分是氧化钙和氢氧化钠，则干燥管A的作用：，若撤去装置A会导致实验结果；干燥管C的作用是；E装置的作用是。
步骤③中鼓气的目的是；步骤⑥中鼓气的目的是，若没有该步骤，会导致实验结果；本实验能否同时省略③、⑥两个步骤，原因是。
⑵若所取样品的质量为5g，为确保实验顺利进行，分液漏斗F中至少要盛放10％的稀硫酸（密度为mL） mL，若m1为，m2为，样品中碳酸钠的质量分数为。
18.下列实验方案中，不能证明氢氧化钠溶液与稀盐酸发生了反应的是（）A．向一定量的氢氧化钠溶液中通入二氧化碳后再滴加稀盐酸，有气体生成B．向装有一定量氢氧化钠溶液的烧杯中滴几滴酚酞溶液，再不断滴入稀盐酸 C．用pH试纸测氢氧化钠溶液pH，再滴加稀盐酸，pH逐渐降低，最终小于7D．向装有少量稀盐酸的试管中滴加足量氢氧化钠溶液，再向其中滴加碳酸钠溶液19.如图为A、B、C三种物质的溶解度曲线，据图回答：（1）t2℃时，A、B、C三种物质的溶解度由大到小顺序是______．（2）将t2℃时三种物质等质量的饱和溶液分别降温到0°C时，析出溶质最多的是______，无溶质析出的是______．（3）20℃时，将30g A物质放入50g水中，充分搅拌，所得溶液的质量是______g．（4）若将t10C三种物质的饱和溶液分别升温到t20C时，则三种溶液中溶质的质量分数由大到小的顺序是______．20.下图是常见固体物质的溶解度曲线，根据图示回答：℃时100g的饱和溶液中含A物质 g①t1②t2℃时，A，B，C的相同质量饱和溶液中，溶剂质量由大到小顺序是③将t1℃一定量A的饱和溶液升温至t3℃时，可用图上点表示④若将t3℃三种物质的饱和溶液分别降温到t1℃，则对所得三种溶液说法正确的是A.都是饱和溶液B.溶质的质量分数B>C>AC.溶剂质量都不变D.析出溶质的质量：A>B>C⑤t2℃时，分别蒸发等质量的A,B,C饱和溶液，析出固体（不含结晶水）的质量的大小关系是。
21.课外小组同学在实验室进行一氧化碳还原氧化铁的实验。
【查阅资料】Ⅰ．常温下，甲酸（HCOOH）是无色易挥发的液体，在浓硫酸作用下易分解。
甲酸分解的化学方程式为：HCOOH CO↑+ HO，浓硫酸在反应中起2作用。
Ⅱ．铁与氯化铁溶液在常温下发生反应生成氯化亚铁。
【实验设计及操作】（1）利用下列装置完成用纯净、干燥的一氧化碳还原氧化铁实验，并检验气态产物（2）①若各步均反应完全，装置的连接顺序为甲→→→→→尾气处理（填序号）。
（3）②实验时先点燃甲中的酒精灯，一段时间后再点燃丁中的酒精喷灯，目的是；装置乙的作用是。
（4）③装置丁中观察到的现象是，反应的化学方程式是。
（5）为检验氧化铁是否反应完全，同学们设计如下实验方案：从装置丁中取出少量反应后的固体粉末于试管中，加入足量稀盐酸，若观察到有大量气泡产生且溶液变为浅绿色而非黄色，则说明氧化铁已完全反应。
上述判断是否正确，理由是。
22.呼吸面具和潜水艇中可用过氧化钠（Na2O2）作为供氧剂．为了探究其反应原理，兴趣小组同学在老师的指导下，进行了如下探究，请你一起参与．[查阅资料]过氧化钠在常温下与水、二氧化碳反应分别生成氢氧化钠、碳酸钠和氧气．[设计实验]浩明同学想通过下图所示装置探究过氧化钠与二氧化碳的反应，并验证反应产物．（1）下列是实验室常用的仪器：①A 是二氧化碳气体的发生装置，装配该装置时，应选用的仪器除带导管的双孔橡皮塞外，还需要的仪器有（填名称）______、______．实验室制取二氧化碳的化学方程式 ．该装置在实验室还可以用来制取氧气，写出用该装置制取氧气的化学方程式②实验室选择制取气体的发生装置，主要依据是 、 ． （2）用D 所示的方法收集氧气，其依据是 ；收集氧气时，还可以选用 法收集．检验D 装置试管内收集到中的气体是否氧气的方法、现象及结论是：待D 中气体集满后，把试管移出水面，然后 ． （3）C 中氢氧化钠的作用是吸收没有参与反应的CO2，如果没有连接这个装置，可能导致的后果是 ． （4）检验B 中反应后剩余固体的成分．实验步骤实验现象实验结论及方程式[反思与评价]通过上述实验，明明同学认为Na2O2与CO2反应除了生成Na2CO3和O2，还有可能生成NaHCO3．你认为他的结论______（选填“正确”或“不正确”），理由是．写出Na2O2与二氧化碳反应的化学方程式．23.图一为甲、乙两种物质（不带结晶水）的溶解度曲线图．Ⅰ．图一中M交点的含义是；Ⅱ．t1℃时，100g甲物质的饱和溶液中含有 g甲，该溶液的溶质质量分数为．Ⅲ．升高温度能够使其饱和溶液转化为不饱和溶液的是（填“甲”或“乙”）．Ⅳ．在t1℃时，A、B两烧杯中均盛有20g水，分别加入等质量的甲、乙两种物质，搅拌后如图二所示，则加入固体的质量必须大于 g．Ⅴ．将两个烧杯中的溶液升温至t2℃，有关A、B两烧杯中的情况，描述正确的是．①溶质质量：A可能等于B ②溶液质量：A一定大于B③溶质质量分数：A可能等于B ④溶剂质量：A一定等于B⑤溶液状态：A一定不饱和，B一定饱和．24.气体的溶解度是指在一定温度和压强下，某气体在1体积水里达到饱和状态时所溶解的体积．为比较温度对气体溶解度的影响，查得101kPa时，M、N两气体在不同温度下的溶解度数值：S M．20℃ =L H2O ，S N，40℃= H2O ．则在101kPa、30℃时，M、N两种气体的溶解度大小关系正确的是（） A．S M＜S N B．S M=S N C．S M＞S N D．无法比较25.不同温度下，氧气的溶解度随压强的变化如图所示，图中t1对应的温度为40℃，则t2对应的温度________（填编号）。