八年级unit10复习总纲(答案版)
人教新目标八年级英语上册复习Unit10精练卷含答案
人教新目标八年级英语上册复习【Unit 10 If you go to the party, you'll have a great time!】精练卷一、单项选择1.—How nice a fly!—Thanks.I made it by ________.A.me B.hers C.itself D.myself2.You won't pass the exams ________ you work hard.A.if B.unless C.so D.and3.—What's the meaning of “secretary”?—Let me ________ the word in the dictionary.A.look at B.look for C.look after D.look up4.—Mrs.Wang was sent to teach English in a poor mountain village last year.—She said she would never forget some pleasant ________ while working there.A.experiments B.expressionsC.experiences D.emotions5.Cindy,why are you so upset? Do you have any problems ________ your homework?A.at B.to C.above D.with6.—How should we teenagers be ________ when crossing the road?—We mustn't run the red traffic lights.A.serious B.careful C.pleased D.popular7.—Wow, Wendy, it's cool to make a short video with your mobile phone.—Just with a software called Meipai. Let me show you ________.A.which to use B.how to use itC.what to use D.where to use it8.Our teachers usually give us some ________ on how to face the difficulties and challenges ________.A.advice;brave B.advices;braveC.advices;bravely D.advice;bravely9.—This is between you and me.—I promise.I won't tell others ________ you say I can.A.unless B.or C.since D.and10.I'm late for school today.I think my teacher must be ________ me.A.worried about B.pleased withC.friendly to D.angry with11.Do you think the worst thing is ________ nothing?A.do B.does C.to do D.done12.He often ________ in spelling last year.A.makes a mistake B.makes mistakesC.made a mistake D.made mistake13.He got ________ before he was famous.A.a education B.an educationC.few education D.any education14.Your son often smokes.Please advise him ________ cigarettes.A.to smoke B.not to smokeC.smoking D.not smoking15.—Do you often help your parents with some housework at home?— ________.I have to wash the dishes after dinner every day.A.Never B.MaybeC.Certainly,I do D.Usually二、完形填空Wang Ling, a middle school girl, felt angry 1 her parents after getting a boy’s phone call. “A classmate called me to discuss homework. We talked for just a few minutes before my parents got mad,” said the girl. “They asked whether I liked the boy. I said I didn’t, 2 they wouldn’t believe me. ”Wang’s trouble is not strange at all because puppy love (早恋) becomes a big headache for 3 parents and schools. They worry that puppy love will be bad for 4 . Her school makes it a rule not to allow any talk or any physical contact (身体接触) 5 one boy and one girl alone. Many students say they understand 6 parents and teachers are so nervous about puppy love. But some think they are going too far. “We have our own thoughts and we know what to 7 with it,” sai d Wang Ling.Another girl, Jiang Ting, liked making friends with boys. “Boys and girls can learn fr om each other,” she said. “My mother asks me to study hard. However, she 8 stops me from making friends with boys. Once Jiang told her mother she might fall in love with a boy. Her mother let Jiang make 9 own decision. Soon Jiang found that she didn’t like him any more because the boy was not as 10 as what she had thought before. And she did worse and worse in her subjects because she spent much on it. At last she understood the worry from schools and most parents about puppy love.1. A. for B. in C. with D. to2. A. because B. if C. but D. and3. A. both B. none C. either D. neither4. A. game B. study C. match D. housework5. A. during B. between C. around D. about6. A. how B. what C. who D. why7. A. play B. live C. do D. fill8. A. never B. already C. ever D. just9. A. its B. my C. his D. her10. A. good B. bad C. heavy D. thin三、阅读理解ASchool ReportsName Jack BrownSchool Hilltop SchoolTerm ending July 8thChemistry He is a little weak in this subject, but he has tried his best to catch up with others.Science He can work out many difficulties. Well done.English He is the best in the class. Keep it up.Spanish His handwriting is very good. He can write good compositions.History He is not so good at this, but he has done better than before.Geography He is familiar with the names of many places in the world.Music He sings very well, but he doesn’t like pop songs.Behavior Better.Have the ability to do a lot better.Remark (评语)Head teacher Lisa SmithHeadmaster Andrew RobinsonDate July 4th1. After reading the form, we know this is __________.A. a study plan of Jack BrownB. a teaching prediction of Lisa SmithC. a school report about Jack BrownD. a working plan of Andrew Robinson2. Which of the following is not mentioned in the form?A. Art.B. Music.C. Chemistry.D. History.3. From the form, we know that Jack’s best subject is __________.A. scienceB. SpanishC. geographyD. English4. From this form, we know Jack is not so good at __________.A. science and geographyB. chemistry and historyC. history and SpanishD. music and English5. According to the form, which of the following is TRUE?A. Jack likes pop music very much.B. Jack doesn’t do well in science.C. Jack can do better if he works harder next term.D. Jack learns six subjects in school.BYou’re going to a foreigner’s party. You must be excited ab out it. Wait a minute! Do you know what kind of gift you can send to your foreign friends? Here are some tips.In some western countries, some gifts like kites, chopsticks (筷子), or an erhu may be people’s favorites.Use beautiful paper to wrap the gifts. Remember not to use white, black or brown paper.For Japanese, gifts like tea or pens are nice. They don’t like big gifts.For Frenchmen, gifts like candy, perfume (香水), wine or books are perfect.British people and Americans like flowers, wine and chocolate, and you can relax and take it easy at their parties.In Arab countries, it’s not polite to send a gift to someone when you meet him or her for the first time. Isn’t that interesting? You can give a gift when you meet a second time.6. In so me western countries, __________ may be people’s favorite gift (s).7. What does the underlined word “wrap” mean in Chinese?A.装饰B.衬托C.捆绑D.包裹8. According to the passage, tea is a good gift for __________.A. JapaneseB. FrenchmenC. AmericansD. British people9. Which of the following is TRUE according to the passage?A. In some western countries, an erhu is not a good gift.B. It’s not a good idea to send flowers to an American girl.C. People from different coun tries have different favorite gifts.D. In Arab countries, we should send a gift to everyone we meet.10. What is the passage mainly about?A. Some tips about the kind of gift we can send to our foreign friends.B. Some ideas about how to make friends with people from ot her countries.C. So me kinds of parties to celebrate one’s birthday.D. Some popular gifts for American people.四、书面表达Mike 是一名中学生,他沉迷于玩电脑游戏,并因此影响了他的学习。
八年级下册复习提纲(填空版)含答案
答卷时应注意事项1、拿到试卷,要认真仔细的先填好自己的考生信息。
2、拿到试卷不要提笔就写,先大致的浏览一遍,有多少大题,每个大题里有几个小题,有什么题型,哪些容易,哪些难,做到心里有底;3、审题,每个题目都要多读几遍,不仅要读大题,还要读小题,不放过每一个字,遇到暂时弄不懂题意的题目,手指点读,多读几遍题目,就能理解题意了;容易混乱的地方也应该多读几遍,比如从小到大,从左到右这样的题;4、每个题目做完了以后,把自己的手从试卷上完全移开,好好的看看有没有被自己的手臂挡住而遗漏的题;试卷第1页和第2页上下衔接的地方一定要注意,仔细看看有没有遗漏的小题;5、中途遇到真的解决不了的难题,注意安排好时间,先把后面会做的做完,再来重新读题,结合平时课堂上所学的知识,解答难题;一定要镇定,不能因此慌了手脚,影响下面的答题;6、卷面要清洁,字迹要清工整,非常重要;7、做完的试卷要检查,这样可以发现刚才可能留下的错误或是可以检查是否有漏题,检查的时候,用手指点读题目,不要管自己的答案,重新分析题意,所有计算题重新计算,判断题重新判断,填空题重新填空,之后把检查的结果与先前做的结果进行对比分析。
亲爱的小朋友,你们好!经过两个月的学习,你们一定有不小的收获吧,用你的自信和智慧,认真答题,相信你一定会闯关成功。
相信你是最棒的!八年级下册知识点梳理复习提纲填空版[植物的生殖]1、种子植物的____属于有性生殖。
有性生殖的后代,具有____2、植物的无性生殖是:____称为无性生殖。
无性生殖产生的后代,只具有____3、在生产实践中,人们常利用植物的无性生殖来栽培农作物和园林植物等,以迅速扩大优良植物新品种的繁殖量和遗传特性的一致性,常见的方式有____4.扦插就是将植物的一段枝条下部插入湿润的土壤中,在适宜的温度下,枝条下部长出不定根,上部发芽,最后长成一个新个体。
如____方法来栽培;____5.嫁接就是把一个植物体的____,接在另一个植物体上____,使结合在一起的两部分长成一个完整的植物体。
(完整版)人教版八年级上册第十单元知识点归纳总结全八上unit10知识点.doc
Unit 10 If you go to the party ,you 'll have a great time重要短go to the party with和⋯⋯一起参加晚会wear jeans to穿⋯牛仔到⋯⋯take the bus to乘公⋯共汽到stay at home 待在家里have a class meeting开班会plan to do 划做make some food 做食物ask sb.to do sth.要某人做某事play the game 做游work hard努力工作/努力学a soccer player 一个足球运,school clean-up 学校大除keep ⋯ to oneself 把⋯留自己 /独 /避免与人交往talk to sb. 与某人in life 在一生中,in the end 在最后be angry at/about sth 因某事而生气,make mistakes 弄 /出差in the future在将来,run away 逃跑the first step 第一步,in half成半solve a problem 解决,Grammar :一、含有if 引的条件状从句的主从复合句由一个主句和一个或一个以上的从句构成的句子叫复合句。
若由接引的句子在复合句中表示条件,作主句的条件状,句子被称条件状从句。
when,as soon as,while , until 等引的状从句,如果主句用一般将来,此状从句与if 引的状从句一,也用一般在代替将来。
1.条件状从句的引。
条件状从句通常由if( 如果,假如), unless(= if ⋯ not,除非,如果不)引。
eg: You will get good grades if you study hard. If you don't leave right away , you will be late.如果你努力学,就会取得好成。
人教版八年级上册第十单元知识点归纳总结全八上unit10知识点(最新整理)
Unit 10 If you go to the party ,you'll have a great time重要短语go to the party with…和……一起参加晚会wear jeans to…穿牛仔裤到……take the bus to…乘公共汽车到stay at home待在家里have a class meeting 开班会plan to do 计划做make some food 做食物ask sb.to do sth.要某人做某事play the game 做游戏work hard 努力工作/努力学习a soccer player 一个足球运动员,school clean-up学校大扫除keep…to oneself 把…留给自己/独处/避免与人交往talk to sb.与某人谈话in life在一生中,in the end 在最后be angry at/about sth 因某事而生气,make mistakes 弄错/出差错in the future 在将来,run away逃跑the first step第一步,in half 成半solve a problem解决难题,Grammar:一、含有if引导的条件状语从句的主从复合句由一个主句和一个或一个以上的从句构成的句子叫复合句。
若由连接词引导的句子在复合句中表示条件,作主句的条件状语,则该句子被称为条件状语从句。
when,assoon as,while,until等引导的时间状语从句,如果主句用一般将来时,此类状语从句与if引导的状语从句一样,也应用一般现在时代替将来时。
1.条件状语从句的引导词。
条件状语从句通常由连词if(如果,假如),unless(=if…not,除非,如果不)引导。
eg:You will get good grades if you study hard.如果你努力学习,就会取得好成绩。
人教版八年级英语UNIT10基础复习题(含答案)
人教版八年级英语UNIT10基础复习题(含答案)一、单项选择1. —Do you know who taught ________ Russian?—Nobody. He learned it by ________.A. his; himselfB. him; himC. him; himselfD. his; him2. He has much ________ as an engineer. So he can build the bridge successfully.A. balanceB. experienceC. surfaceD. service3. We advise parents ________ the children stay at home all day. Children should get close to nature.A. not makeB. not to makeC. makeD. to make4. I'm late for school today. I think my teacher must be very ________ me.A. crazy aboutB. pleased withC. friendly toD. angry with5. I'll be with you forever. Please ________ me.A. knowB. missC. hateD. trust6. He felt ________surprised ________ say a word with his mouth wide open.A. too; soB. too; toC. so; thatD. so; to7. You must be ________ and never make the same mistake.A. more carelessB. carefullyC. more carefulD. careless8. —Is your WeChat account safe?—Yes, even my father can't use it ________ I tell him the password.A. whenB. unlessC. whileD. if9. —If the traffic ________ busy, Linda won't catch the train in one hour.—I know. I will call her to leave for the train station at once.A. isB. will beC. wasD. has been10. —What about going to Shanghai Disneyland Park next month, Harry?—________! We'll have a lot of fun there.A. Good luckB. Never mindC. Sounds greatD. Certainly not二、完形填空When I was in middle school, I felt I was always letting people down. Once I brought my ________11 Daisy to my home. I noticed that all my family members seemed to ________12 Daisy better than me.I felt very ________13. I even thought they didn't love me. I wondered whether they would miss me if I died some day. ________14 I told my mum, “Daisy is more patient than I am. You must want her to be your daughter instead of me.”My mum explained that Daisy was a lovely girl, but ________15 could replace me in the family. She said I was the only person who could fill my role. She made me realize that even if I made ________16, I was a beloved member of the family who could never be replaced.From then on, I tried to ________17 out who I was and what made me special. I looked at ________18 in a new way. Then I started to be positive(积极的) towards my life, and I was happy about who I ________19 was. I came to feel much better as I knew that no one could ever replace me.Each of us holds a special place in the world. You are special, no matter what others say or what you may think. So ________20 that you will be replaced. You can't be.11. A. daughter B. son C. friend D. uncle12. A. like B. know C. understand D. learn13. A. lucky B. sad C. bored D. glad14. A. But B. So C. Though D. Whether15. A. anybody B. somebody C. everybody D. nobody16. A. mistakes B. faces C. wishes D. decisions17. A. put B. find C. look D. clear18. A. itself B. herself C. himself D. myself19. A. nearly B. hardly C. really D. almost20. A. forget B. worry C. consider D. think三、阅读理解Dear Merry,These days, I have problems with my study. In school I can't listen to teachers carefully because I always feel tired and sleepy. I don't spend time with friends after class either, because I think it's a waste of time. I even miss writing some answers in the test.At home, I can't get my homework done every night. My parents don't let me stay up. So I have to get up early the next morning to finish it. Lately, I even get a bad headache.How can I solve these problems?Yours,Liu Ya Dear Liu Ya,When you have problems listening to teachers carefully in class, you can ask your teachers or deskmate to remind you often. Then spending time talking about many different things with friends can make you happy. It's not a waste of time.As for homework, when it's hard to get it finished, one thing you can try is to set goals for yourself. Ask your parents to help you. You must take a break if you don't feel well. You might be surprised but a short rest can help you a lot! Lastly, if you don't worry and have enough sleep, your headache will leave you.Yours,Merry21. Liu Ya wrote the letter to Merry in order to ________.A. ask for helpB. express worriesC. share her experienceD. share her happiness22. Liu Ya doesn't want to stay with friends after class because ________.A. she needs to sleepB. she thinks it's a waste of timeC. she has problems with her classmatesD. she is afraid of talking with others23. Merry thinks ________.A. taking a rest is necessaryB. being with parents is helpfulC. setting goals by parents is importantD. listening to music is necessary24. According to the underlined part, what might Liu Ya's teacher say to remind her?A. Sleep for a minute.B. Listen carefully.C. Stop talking.D. Well done.25. From Liu Ya's letter, we can find that she is too ________.A. happyB. carelessC. nervousD. excited四、词汇运用A)根据句意及汉语提示, 填写恰当的单词26. What ________(其他的) should we do?27. We should encourage(鼓励)________(青少年) to take part in more socialactivities.28. The first ________(步骤) is very important.29. How do you plan and________(组织) the meeting?30. He is able to lead a ________(正常的)life.B)用所给词的适当形式填空31. Your brother is ________(certain) a good student.32. There are some spelling________(mistake) in your homework.33. The girl is kind and____________(understand). Everyone likes her.34. We have a class ________(meet) every Friday afternoon.35. They ________(solve) the problem successfully the day before yesterday.五、语法填空G 36 up is not always easy. When you face p 37, what should you do? Just sit there and wait for help? Or believe y 38? Doing by yourself is more useful than crying for help.Studying makes you tired. H 39 to deal with the stress and relax yourself? Here is some a 40 which may add happiness to your life.Stress and w 41 are your body's enemies. Life isn't just study, study, study. Though s 42 is important, it's equally important to enjoy yourself, such as listening to music, doing sports, having a meal or going out for a travel. No doubt you have some wonderful f 43, family, and a roof over your head, so just talk to them and s 44 what troubles you with them. Follow the above advice, you can s 45 your problems sooner or later.Unit 10测试一、1. C2. B3. B4. D5. D6. B7. C8. B9. A10. C二、11. C12. A13. B14. B15. D16. A17. B18. D19. C20. A三、21. A22. B23. A24. B25. C26. else27. teenagers28. step29. organise/organize30. normal31. certainly32. mistakes33. understanding34. meeting35. solved五、36. Growing37. problems38. yourself39. How40. advice41. worries42. schoolwork/study43. friends44. share45. solve。
2019-2020人教版八年级英语上册unit10基础知识点期末复习及训练(含答案)
2019-2020人教版八年级英语上册Unit10基础知识点期末复习及训练(含答案)Unit 10 If you go to the party, you will have a great time基础知识点复习一、重点短语复习1.stay at home待在家里2.take the bus乘公共汽车3.tomorrow night明天晚上4.have a class party进行班级聚会5.half the class一半的同学6.make some food做些食物7.order food订购食物8.have a class meeting开班会9.at the party在聚会上10.potato chips炸土豆片,炸薯条11.in the end最后12.make mistakes犯错误13.go to the party去参加聚会14.have a great/good 玩得开心15.give sb. some 16.advice给某人提一些建议17.go to college上大学18.make(a lot of)money赚(许多)钱19.travel around the world环游世20. careless adj. 粗心的;反义词:careful,意为“小心的”。
21. advise doing sth. 建议做某事;advise sb.(not)to do sth. 建议某人(不)做某事22. run away from“ 从…逃离” “逃避”23. cut …in half “切成两半”24.tell sb. to do sth. 告诉某人做某事25.too…to do sth.太……而不能做某事26.be afraid to do sth. 害怕做某事27.need to do sth. 需要做某事二、重点句型1. It’s best (not) to do sth.最好(不)做某事2.give sb. some advice给某人提一些建议3.tell sb. to do sth. 告诉某人做某事4. have a great time 意为“玩得愉快”,=enjoy oneself, = have fun, =have a good / wonderful / nice time5.have a great / good time in (doing) sth. 做某事很开心6.be afraid +that从句例:I’m afraid that I can’t finish on time7. It’s best (not) to do sth. 最好(不)做某事例:It’s best to speak English every day.三、易错知识点辨析1. be afraid to do sth. 害怕干某事例句1、I’m afraid to speak in front of other people.be afraid of sth. 害怕某事例句2、He told me not to be afraid of difficulties.be afraid +that从句例句3、I’m afraid that I can’t finish on time2. a dvise v.“劝告;建议”n. advice, 是不可数名词.例句1、Give me some advice!advise doing sth. 建议做某事。
甘肃西北师大附中人教版初中英语八年级上册Starter Unit 10知识点总结(含答案)
考试范围:xxx;满分:***分;考试时间:100分钟;命题人:xxx 学校:__________ 姓名:__________ 班级:__________ 考号:__________一、选择题1.一How do you like this plan?— It's just what I've been expecting.A.Perfect. B.Terrible. C.Meaningless D.Awful2.Now many people in the countryside leave their hometown to ________ work in big cities.A.wait for B.take inC.search for D.find out3.--What a nice bike!But I have no money to buy it.-- .A.That’s all right.B.So it does.C.That sounds boring.D.It’s a shame!4.I have had the schoolbag ______ 10 years ago.A.for B.when C.since D.as5.I want to______information about robots on the Internet.A.wait for B.ask for C.search for D.go for6.—As we know,it's difficult to live in a foreign country.—______ if you can't understand the language there.A.Exactly B.Naturally C.Usually D.Especially 7.Miss Miller is nice and teaches well. She is very popular ________ the students. A.inside B.betweenC.among D.around8.Could you please help ________ the information about the pa ssengers? I’m busy now. A.bring out B.check out C.work out D.give out 9.Peter, honest boy, bought useful dictionary in the store yesterday.A.a; a B.an; an C.a; an D.an; a 10.Maybe we should go down to the library and ______.A.checks it B.check it inC.check it out D.checked it up11.— Can you give me some information about vacation trips?— Why not ______ going to Hainan Island?A.consider B.mind C.keep D.take12.Can you help me those exercise books? I got a different number each time. A.carry B.move C.write D.count13.________, I can't afford the expensive gift.A.To my surprise B.To be honestC.To start with D.To begin with14.I made a phone call to Jack's teacher to his mark. I wanted his right mark. A.give up B.check out C.clear out 15.—Time past can not be called back again.—Yes. Wasting time is a .A.pressure B.fairness C.choice D.shame16.﹣As we know, its very difficult to live in a foreign country like the UK, the US and so on.﹣I agree._____ if you don't understand the local language.A.Especially B.Generally C.Naturally D.Exactly 17.—I haven’t been back to my hometown for years.—________!Your parents must miss you very much.A.Of course B.No problemC.What a shame D.Thank you18.There are smiles everywhere,________ on the faces of children.A.nearly B.especially C.finally D.luckily 19.Tom________ a lot of friends since he came to China last year.A.made B.makes C.is making D.has made 20.—We lost the basketball game against Class 5. — ______.A.My pleasure B.No problem C.It’s a shame D.Sounds great 21.The TV show Letters Alive brings back people's of writing to each other.A.ideas B.hobbies C.styles D.memories 22.The ship was full of people. There was no______ for Elen.A.room B.rooms C.a room D.any room 23.Zhang Li has been working for______ eight hours.A.the whole B.the all C.whole D .all24.-How many times_____ to Shanghai since the summer of 2002?-Twice.A.did you go B.have you gone C.have you been D.will you go 25.Rick has learned a lot about Chinese culture _______ he came to China.A.before B.when C.until D.since 26.Mary always does well in her lessons. She works the hardest ________ all the students. A.among B.during C.between D.through【参考答案】一、选择题1.A 2.C 3.D 4.C 5.C 6.D 7.C8.B 9.D 10.C 11.A 12.D 13.B 14.B 15.D 16.A 17.C 18.B 19.D 20.C 21.D 22.A 23.A 24.C 25.D【参考解析】一、选择题1.A解析:A【详解】句意:——你觉得这个计划怎么样?——很完美。
八年级数学下册第10章分式复习学案苏科版
分式【学习目标】1.了解分式方程的定义,会解分式方程,能够判断分式方程的增根.2.掌握解分式方程的一般步骤,能够根据分式方程的条件解求参数的值或取值范围. 3.能够运用分式方程解决实际类问题,体会数学源于生活,但高于生活. 【知识点】1.分式方程:指含分式,且分母中含有未知数的方程. 2.解分式方程的步骤:(1)能化简的先化简.(2)去分母,把方程两边同乘以各分母的最简公分母(产生增根的过程). (3)解整式方程,得到整式方程的解.(4)检验,把所得的整式方程的解代入最简公分母中:如果最简公分母为0,则原方程无解,这个未知数的值是原方程的增根;如果最简公分母不为0,则是原方程的解. 注意:产生增根的条件是:①是得到的整式方程的解;②代入最简公分母后值为0.3.列分式方程解决实际问题的基本步骤:审,设,列,解,答(跟一元一次不等式组的应用题解法一样).①审—仔细审题,找出等量关系. ②设—合理设未知数.③列—根据等量关系列出方程(组). ④解—解出方程(组),注意检验. ⑤答—答题. 【例题精讲】一、分式方程的定义 例1.(1)下列方程:①25x =;②52x =;③23y x =;④1152x x +=+;⑤21y y +=;⑥13(2)7x x +-=-;⑦233yy -=.其中分式方程的个数是 A .1 B .2 C .3 D .4 (2)下列方程中是分式方程的是A .xx ππ=B .111235x y +=C .x b x a b π-=(a 、b 为常数)D .11132x x +--=-(3)下列方程中,不是分式方程的是 A .21xx -= B 1223x +=-+C .22112x x x x ++=+ D 2112x x +=-例2.(1)下列方程是关于x 的方程,其中是分式方程的是 (只填序号). ①52ax b +=;②15()243x x b +++=;③2m x m x a a +-+=;④2221x x x =-;⑤1312x x +=-;⑥a b a b x a ++=;⑦111b a x b x -=-;⑧2x b x ba a-+=+.(2)观察分析下列方程:①23x x +=;②65x x +=;③127x x+=,请利用他们所蕴含的规律,写出这一组方程中的第n 个方程是 .二、分式方程的解例1.(1)若关于x 的方程3333x m mx x++=--的解为正数,则m 的取值范围是 A .92m < B .92m <且32m ≠C .94m >-D .94m >-且34m ≠-(2)若关于x 的分式方程2122x a x -=-的解为非负数,则a 的取值范围是A .1a ≥B .1a ≥且4a ≠C .1a >D .1a >且4a ≠(3)若x 的方程2222x mx x ++=--的解为正数,关于y 的不等式组22(2)y m y m m -≥⎧⎨-≤+⎩有解,则符合题意的整数m 的个数有A .4B .5C .6D .7(4)若关于x 的方程2222x m x x ++=--的解为正数,则m 的取值范围是 . (5)若关于x 的分式方程111k x kx x ++=+-的解为负数,则k 的取值范围是 .(6)已知关于x 的方程24x m-=的解是负数,则m 的取值范围为 .(2)若关于x 的分式方程1m x=-无解,则m 的值为 A .0 B .2 C .0或2 D .±2 (3)关于x 的方程223242mx x x x +=--+有增根,则m 的值为 A .﹣4 B .6 C .﹣4和6 D .0 (4)关于x 的方程223242mx x x x +=--+无解,则m 的值为 . (5)若关于x 的分式方程526(1)1x k x x x x +=---有增根,则k 的值为 . (6)已知关于x 的分式方程22024mxx x +=--有增根且m ≠0,则m = . (7)已知关于x 的分式方程22024mxx x +=--有无解且m ≠0,则m = .三、分式方程及其应用 例1.(1)一艘轮船在静水中的最大航速为30km/h ,它以最大航速沿江顺流航行90km 所用时间,与以最大航速逆流航行60km 所用时间相等.设江水的流速为vkm/h ,根据题意,下列所列方程正确的是A.90603030v v=+-B.906030v v=-C.90603030v v=-+D.906030v v=-(2)A,B两地相距180km,新修的高速公路开通后,在A,B两地间行驶的长途客车平均车速提高了50%,而从A地到B地的时间缩短了1h.若设原来的平均车速为xkm/h,则根据题意可列方程为A.1801801(150%)x x-=+B.1801801(150%)x x-=+C.1801801(150%)x x-=-D.1801801(150%)x x-=-(3)某市需要铺设一条长660米的管道,为尽量减少施工对城市交通造成的影响,实际施工时,每天铺设管道的长度比原计划增加10%,结果提前6天完成.求实际每天铺设管道的长度与实际施工天数.根据题意列出方程:6606606(110%)x x-=+.则方程中未知数x所表示的量是A.实际每天铺设管道的长度 B.实际施工的天数C.原计划每天铺设管道的长度 D.原计划施工的天数(4)端午节那天,“味美早餐店”的粽子打9折出售,小红的妈妈去该店买粽子花了54元钱,比平时多买了3个,求平时每个粽子卖多少元?设平时每个粽子卖x元,列方程为.(5)某校学生捐款支援地震灾区,第一次捐款总额为6600元,第二次捐款总额为7260元,第二次捐款人数比第一次多30人,而且两次人均捐款额恰好相等.求第一次的捐款人数.设第一次的捐款人数是x人,根据题意得方程:.(6)某道路需要铺设一条长1200米的管道,为了尽量减少施工对交通造成的影响,施工时,工作效率比原计划提高了25%,结果提前了6天完成任务,设原计划每天铺设管道x米,根据题意列出方程为.(7)今年6月1日起,国家实施了中央财政补贴条例支持高效节能电器的推广使用,某款定速空调在条例实施后,每购买一台,客户可获财政补贴200元,若同样用11万元所购买的此款空调台数,条例实施后比实施前多10%,则条例实施前此款空调的售价为元.例2.为了响应“十三五”规划中提出的绿色环保的倡议,某校文印室提出了每个人都践行“双面打印,节约用纸”.已知打印一份资料,如果用A4厚型纸单面打印,总质量为400克,将其全部改成双面打印,用纸将减少一半;如果用A4薄型纸双面打印,这份资料的总质量为160克,已知每页薄型纸比厚型纸轻0.8克,求A4薄型纸每页的质量.(墨的质量忽略不计)例3.根据城市规划设计,某市工程队准备为该城市修建一条长4800米的公路.铺设600m后,为了尽量减少施工对城市交通造成的影响,该工程队增加人力,实际每天修建公路的长度是原计划的2倍,结果9天完成任务,该工程队原计划每天铺设公路多少米?例4.某超市用3000元购进某种干果销售,由于销售状况良好,超市又调拨9000元资金购进该种干果,但这次的进价比第一次的进价提高了20%,购进干果数量是第一次的2倍还多300千克,求该种干果的第一次进价是每千克多少元?例5.小王到某中式快餐店用餐,该快餐店的招牌餐是卤肉套饭和红烧肉套饭,其中每份红烧肉套饭比卤肉套饭贵了3元钱,小王发现若用150元买卤肉套饭数量是用90元买到的红烧肉套饭数量的两倍.(1)请帮小王计算一份卤肉套饭和一份红烧肉套饭售价各多少元?(2)该快餐店决定将成本为10元的卤肉套饭与成本为11.5元的红烧肉套饭采取送餐上门的销售形式,将每份卤肉套饭和红烧肉套饭在原售价基础上分别涨价20%和25%,这样一来,快餐店平均每天要多支出20元的交通成本(每月按30天算)和每份0.5元的打包成本.而该店每月只外送500份套餐,问:至多送出多少份卤肉套饭可产生不低于3600元的利润?【课堂练习】1.下列关于x 的方程中,是分式方程的是A .132x =B .2354x x ++=C .12x= D .321x y -= 2.关于x 的分式方程3111m x x+=--的解为正数,则m 的取值范围是A .2m >B .2m >且3m ≠C .2m <D .3m <且2m ≠3.某服装店用10000元购进一批某品牌夏季衬衫若干件,很快售完;该店又用14700元钱购进第二批这种衬衫,所进件数比第一批多40%,每件衬衫的进价比第一批每件衬衫的进价多10元,求第一批购进多少件衬衫?设第一批购进x 件衬衫,则所列方程为 A .100001470010(140%)x x -=+ B .100001470010(140%)x x +=+ C .100001470010(140%)x x -=- D .100001470010(140%)x x +=-4.解方程225111mx x x +=+--会产生增根,则m 等于 A .﹣10 B .﹣10或﹣3 C .﹣3 D .﹣10或﹣45.若4x =是方程348x x a+=-的解,则a = . 6.若关于x 的分式方程11222mx x x -+=--有整数解,整数m 的值是 .7.某服装加工厂计划加工400套运动服,在加工完160套后,采用了新技术,工作效率比原计划提高了20%,结果提前2天完成全部任务.则采用技术后每天加工 套运动服. 8.解分式方程:(1)2533322x x x x --=---; (2)2321212141x x x x +-=+--.9.随着人们环保意识的增强及科学技术的进步,各种绿色环保新产品进入千家万户,今年一月份小楠家将天然气热水器换成了太阳能热水器,减少天然气的用量,去年12月份小楠家的天然气费一共是96元,从今年一月份起天然气费价格每立方米上涨了25%,小楠家2月份的用气量比去年12月份少10立方米,2月份的天然气费一共是90元,请你求小楠家今年2月份用气量是多少?【课后作业】1.下列方程中,不是分式方程的是 A .21x x -= B .12231x x +=-++ C .22112x x x x ++=+ D .21212x x x +=- 2.若关于x 的方程322133x mx x x---=---无解,则m 的值是A .53B .3C .53或1D .53或33.某市从今年1月1日起调整居民用水价格,每立方米水费上涨13.小丽家去年12月份的水费是15元,而今年5月的水费则是30元.已知小丽家今年5月的用水量比去年12月 的用水量多5m 3.求该市今年居民用水的价格.设去年居民用水价格为x 元/m 3,根据 题意列方程,正确的是A .301551(1)3x x -=+ B .301551(1)3xx -=- C .301551(1)3x x -=+ D .301551(1)3x x-=-4.若分式11m +有意义,且关于x 的分式方程231x mx -=+的解是负数,则m 的取值范围在数轴上表示正确的是A BC D 5.若关于x 的分式方程1322m xx x-=---有增根,则实数m 的值是 . 6.某网店老板经营销售甲、乙两种款式的浮潜装备,每件甲种款式的利润率为30%,每件乙种款式的利润率为50%,当售出的乙种款式的件数比甲种款式的件数少40%时,这个老板得到的总利润率是40%;当售出的乙种款式的件数比甲种种款式的件数多80%时,这个老板得到的总利润率是 . 7.解分式方程:(1)13213231x x -=--; (2)2243242x x x x +=--+.8.为厉行节能减排,倡导绿色出行,今年3月以来“共享单车”(俗称“小黄车”)公益活动登陆我市中心城区.某公司拟在甲、乙两个街道社区投放一批“小黄车”,这批自行车 包括A 、B 两种不同款型,请回答下列问题: 问题1:单价该公司早期在甲街区进行了试点投放,共投放A 、B 两型自行车各50辆,投放成本共计 7500元,其中B 型车的成本单价比A 型车高10元,A 、B 两型自行车的单价各是多少?问题2:投放方式该公司决定采取如下投放方式:甲街区每1000人投放a 辆“小黄车”,乙街区每1000人 投放8240a a+辆“小黄车”,按照这种投放方式,甲街区共投放1500辆,乙街区共投放 1200辆,如果两个街区共有15万人,试求a 的值.2019-2020学年初二下学期期末数学模拟试卷一、选择题(每题只有一个答案正确)1.数名射击运动员的第一轮比赛成绩如下表所示,则他们本轮比赛的平均成绩是( )环数/环7 8 9 10人数/人 4 2 3 1A.7.8环B.7.9环C.8.1环D.8.2环2.如图,菱形ABCD中,∠A是锐角,E为边AD上一点,△ABE沿着BE折叠,使点A的对应点F 恰好落在边CD上,连接EF,BF,给出下列结论:①若∠A=70°,则∠ABE=35°;②若点F是CD的中点,则S△ABE13=S菱形ABCD下列判断正确的是()A.①,②都对B.①,②都错C.①对,②错D.①错,②对3.用图象法解某二元一次方程组时,在同一直角坐标系中作出相应的两个一次函数的图象(如图所示),则所解的二元一次方程组是().A.202+10x yx y+-=⎧⎨-=⎩B.3210210x yx y--=⎧⎨--=⎩C.3250210x yx y--=⎧⎨+-=⎩D.202-10x yx y+-=⎧⎨-=⎩4.如图,已知ABC,点D、E、F分别是AB、AC、BC的中点,下列表示不正确的是()A .AD AE =B .//DE BCC .DB FE =-D .DB DE FE DE ++=5.在平面直角坐标系中,若点与点关于原点对称,则点在( )A .第一象限B .第二象限C .第三象限D .第四象限6.关于x 的一元二次方程x 2+4x+k=0有两个实数根,则k 的取值范围是( ) A .k≤﹣4 B .k <﹣4C .k≤4D .k <47.函数y =5x -中,自变量x 的取值范围在数轴上表示正确的是( )A .B .C .D .8.某地区连续10天的最高气温统计如下表,则该地区这10天最高气温的中位数是( ) 最高气温(C ︒) 18 19 20 21 22 天数 122 32A .20C ︒B .20.5C ︒C .21C ︒D .21.5C ︒9.如图,在△ABC 中,AC=BC ,∠ACB=90°,AD 平分∠BAC ,与BC 相交于点F ,过点B 作BE ⊥AD 于点D ,交AC 延长线于点E ,过点C 作CH ⊥AB 于点H ,交AF 于点G ,则下列结论:;2;AF BE AF BD DG DE BC CG AB ===+=①②;③;④⑤ACG AGH S S =△△;正确的有( )个.A .1B .2C .3D .410.当分式3-1x 有意义时,字母x 应满足( ) A .x ≠1 B .x =0C .x ≠-1D .x ≠3二、填空题 11.已知函数2x y +=,则自变量x 的取值范围是___________________. 12.用反证法证明“若2a <,则24a <”时,应假设_____.13.某初中校女子排球队队员的年龄分布: 年龄/(岁) 13 14 15 16 频数1452该校女子排球队队员的平均年龄是_____岁.(结果精确到0.1)14.如图,点A 在线段BG 上,四边形ABCD 和四边形DEFG 都是正方形,面积分别是10和19,则△CDE 的面积为_____________.15.如图所示的是用大小相同(黑白两种颜色)的正方形砖铺成的地板,一宝物藏在某一块正方形砖下面,宝物在白色区域的概率是 .16.把长为20,宽为a 的长方形纸片(10<a <20),如图那样折一下,剪下一个边长等于长方形宽度的正方形(称为第一次操作);再把剩下的长方形如图那样折一下,剪下一个边长等于此时长方形宽度的正方形(称为第二次操作);如此反复操作下去,若在第n 次操作后,剩下的长方形为正方形,则操作停止.当n=3时,a 的值为________.17.如图(1),已知小正方形ABCD 的面积为1,把它的各边延长一倍得新正方形1111D C B A ;把正方形1111D C B A 边长按原法延长一倍得到正方形2222A B C D 如图(2);以此下去⋯⋯,则正方形5555A B C D 的面积为_________________.三、解答题18.某市共有三个郊县,各郊县的人数及人均耕地面积如下表所示:郊县人数(万人)人均耕地面积(公顷)A20 0.15B 5 0.20C10 0.18求该市郊县所有人口的人均耕地面积.(精确到0.01公顷)19.(6分)如图,E、F是平行四边形ABCD的对角线AC上的点,且CE=AF. 求证:BE∥DF.20.(6分)关于x、y的方程组233x y kx y+=⎧⎨+=⎩的解满足x﹣2y≥1,求满足条件的k的最大整数值.21.(6分)如图,平行四边形ABCD中,对角线AC,BD相交于点O,点E,F分别是OB,OD的中点,试说明四边形AECF是平行四边形.22.(8分)如图,分别以Rt△ ABC 的直角边AC 及斜边AB 向外作等边△ ACD,等边△ ABE.已知∠ABC=60°,EF⊥AB,垂足为F,连接DF.(1)证明:△ACB≌△EFB;(2)求证:四边形ADFE 是平行四边形.23.(8分)已知矩形ABCD的一条边AD=8,E是BC边上的一点,将矩形ABCD沿折痕AE折叠,使得顶点B落在CD边上的点P处,PC=4(如图1).(1)求AB的长;(2)擦去折痕AE,连结PB,设M是线段PA的一个动点(点M与点P、A不重合).N是AB沿长线上的一个动点,并且满足PM=BN.过点M作MH⊥PB,垂足为H,连结MN交PB于点F(如图2).①若M是PA的中点,求MH的长;②试问当点M、N在移动过程中,线段FH的长度是否发生变化?若变化,说明理由;若不变,求出线段FH的长度.24.(10分)计算:(22+33)2﹣212×3÷52.25.(10分)温度的变化是人们经常谈论的话题,请根据下图解决下列问题.(1)这一天的最高温度是多少?是在几时到达的?(2)这一天的温差是多少?从最低温度到最高温度经过多长时间?(3)在什么时间范围内温度在上升?在什么时间范围内温度在下降?参考答案一、选择题(每题只有一个答案正确)1.C【解析】 由题意可知:这些运动员本轮比赛的平均成绩为(环).故选C . 2.A【解析】【分析】只要证明BF BC =,可得ABF BFC C 70∠∠∠===,即可得出ABE 35∠=;延长EF 交BC 的延长线于M ,只要证明DEF ≌CMF ,推出EF FM =,可得EMB BCDE S S =四边形,BEF MBE 1S S 2=,推出ABE ABCD 1S S 3菱形=. 【详解】①∵四边形ABCD 是菱形,∴AB ∥CD ,∠C=∠A=70°.∵BA=BF=BC ,∴∠BFC=∠C=70°,∴∠ABF=∠BFC=70°,∴∠ABE 12=∠ABF=35°,故①正确; ②如图,延长EF 交BC 的延长线于M ,∵四边形ABCD 是菱形,F 是CD 中点,∴DF=CF ,∠D=∠FCM ,∠EFD=∠MFC ,∴△DEF ≌△CMF ,∴EF=FM ,∴S 四边形BCDE =S △EMB ,S △BEF 12=S △MBE ,∴S △BEF 12=S 四边形BCDE ,∴S △ABE 13=S 菱形ABCD .故②正确,故选A .【点睛】本题考查了菱形的性质、等腰三角形的判定和性质、全等三角形的判定和性质等知识,解题的关键是学会添加常用辅助线,构造全等三角形解决问题.3.D【解析】【分析】由图易知两条直线分别经过(1,1)、(0,-1)两点和(0,2)、(1,1)两点,设出两个函数的解析式,然后利用待定系数法求出解析式,再根据所求的解析式写出对应的二元一次方程,然后组成方程组便可解答此题.【详解】由图知,设经过(1,1)、(0,-1)的直线解析式为y=ax+b (a≠0).将(1,1)、(0,-1)两点坐标代入解析式中,解得21a b ==-⎧⎨⎩ 故过(1,1)、(0,-1)的直线解析式y=2x-1,对应的二元一次方程为2x-y-1=0.设经过(0,2)、(1,1)的直线解析式为y=kx+h (k≠0).将(0,2)、(1,1)两点代入解析式中,解得12k h =-=⎧⎨⎩ 故过(0,2)、(1,1)的直线解析式为y=-x+2,对应的二元一次方程为x+y-2=0.因此两个函数所对应的二元一次方程组是202-10x y x y +-=⎧⎨-=⎩故选D【点睛】此题考查一次函数与二元一次方程(组),解题关键在于要写出两个函数所对应的二元一次方程组,需先求出两个函数的解析式.4.A【解析】【分析】根据中位线的性质可得DB=EF=AD ,且DB ∥EF ,DE=BF ,且DF ∥BF ,再结合向量的计算规则,分别判断各选项即可.【详解】∵点D 、E 、F 分别是AB 、AC 、BC 的中点∴FE ∥BD ,且EF=DB=AD同理,DE ∥BF ,且DE=BFA 中,∵未告知AC=AB ,∴AD 、AE 无大小关系,且方向也不同,错误;B 中,DE ∥BC ,正确;C 中,DB=EF ,且DB 与FE 方向相反,∴DB FE =-,正确;D 中,DB DE FE DB FE DE DE ++=++=,正确故选:A【点睛】本题考查中位线定理和向量的简单计算,解题关键是利用中位线定理,得出各边之间的大小和位置关系.5.C【解析】【分析】直接利用关于关于原点对称点的性质得出m,n的值,进而得出答案.【详解】解:∵点M(m,n)与点Q(−2,3)关于原点对称,∴m=2,n=−3,则点P(m+n,n)为(−1,−3),在第三象限.故选:C.【点睛】此题主要考查了关于原点对称的点的性质,正确得出m,n的值是解题关键.6.C【解析】【分析】根据判别式的意义得△=12﹣1k≥0,然后解不等式即可.【详解】根据题意得△=12﹣1k≥0,解得k≤1.故选C.【点睛】本题考查了根的判别式:一元二次方程ax2+bx+c=0(a≠0)的根与△=b2﹣1ac有如下关系:当△>0时,方程有两个不相等的实数根;当△=0时,方程有两个相等的实数根;当△<0时,方程无实数根.7.B【解析】【分析】根据函数y可得出x-1≥0,再解出一元一次不等式即可.【详解】由题意得,x-1≥0,解得x≥1.在数轴上表示如下:故选B.【点睛】本题要考查的是一元一次不等式的解法以及二次根式成立得出判定,熟练掌握一元一次不等式的解法是本题的解题关键.8.B【解析】【分析】求中位数要把数据按从小到大的顺序排列,位于最中间的一个数或两个数的平均数为中位数.【详解】把这些数从小到大为:18℃,19℃,19℃,20℃,20℃,21℃,21℃,21℃,22℃,22℃,则中位数是:20212=20.5℃;故选B.【点睛】考查中位数问题,注意找中位数的时候一定要先排好顺序,然后再根据奇数和偶数个来确定中位数.如果数据有奇数个,则正中间的数字即为所求;如果是偶数个,则找中间两位数的平均数.9.D【解析】【分析】①②正确,只要证明△BCE≌△ACF,△ADB≌△ADE即可解决问题;③正确,只要证明GB=GA,得到△BDG是等腰直角三角形,即可得到;④正确,求出∠CGF=67.5°=∠CFG,则CF=CG=CE,然后AE=AC+CE=BC+CG,即可得到结论;⑤错误,作GM⊥AC于M.利用角平分线的性质定理即可证明;【详解】解:∵AD⊥BE,∴∠FDB=∠FCA=90°,∵∠BFD=∠AFC,∴∠DBF=∠FAC,∵∠BCE=∠ACF=90°,BC=AC,∴△BCE≌△ACF,∴EC=CF,AF=BE,故①正确,∵∠DAB=∠DAE,AD=AD,∠ADB=∠ADE=90°,∴△ADB≌△ADE,∴BD=DE,∴AF=BE=2BD,故②正确,如图,连接BG,∵CH⊥AB,AC=AB,∴BH=AH,∠BHG=∠AHG=90°∵HG=HG,∴△AGH≌△BGH,∴BG=AG,∠GAH=∠GBH=22.5°,∴∠DGB=∠GAH+∠GBH=45°,∴△BDG是等腰直角三角形,∴BD=DG=DE;故③正确;由△ACH是等腰直角三角形,∴∠ACG=45°,∴∠CGF=45°+22.5°=67.5°,∵∠CFG=∠DFB=90°-22.5°=67.5°,∴∠CGF=∠CFG,∴CG=CF,∵AB=AE,BC=AC,CE=CF=CG,又∵AE=AC+CE,∴AB=BC+CG,故④正确;作GM⊥AC于M,由角平分线性质,GH=GM,∴△AGH≌△AGM(HL),∴△AGH 的面积与△AGM 的面积相等,故⑤错误;综合上述,正确的结论有:①②③④;故选择:D.【点睛】本题考查全等三角形的判定和性质、直角三角形斜边中线的性质、等腰直角三角形的性质、角平分线的性质定理等知识,解题的关键是熟练掌握基本知识,属于中考选择题中的压轴题.10.A【解析】【分析】分式有意义,分母不为零.【详解】解:当10x -≠,即1x ≠时,分式31x -有意义; 故选:A .【点睛】本题考查了分式有意义的条件.(1)若分式无意义,则分母为零;(2)若分式有意义,则分母不为零.二、填空题11.23x x ≥-≠且【解析】分析:根据函数的自变量取值范围的确定方法,从分式和二次根式有意义的条件列不等式求解即可. 详解:由题意可得2030x x +≥⎧⎨-≠⎩解得x≥-2且x≠3.故答案为:x≥-2且x≠3.点睛:此题主要考查了函数的自变量的取值范围,关键是明确函数的构成:二次根式的被开方数为非负数,分式的分母不等于0等条件.12.24a【解析】【分析】反证法的步骤中,第一步是假设结论不成立,反面成立,可据此进行判断.【详解】 解:用反证法证明“若2a <,则24a <”时,应假设24a .故答案为:24a.【点睛】此题主要考查了反证法,解此题关键要懂得反证法的意义及步骤.在假设结论不成立时要注意考虑结论的反面所有可能的情况,如果只有一种,那么否定一种就可以了,如果有多种情况,则必须一一否定.13.14.1.【解析】【分析】根据加权平均数的计算公式把所有人的年龄数加起来,再除以总人数即可.【详解】该校女子排球队队员的平均年龄是131+1441551621452⨯⨯+⨯+⨯+++≈14.1(岁),故答案为:14.1.【点睛】此题考查了加权平均数,掌握加权平均数的计算公式是解题的关键,是一道基础题.14.310 2【解析】【分析】根据三角形的面积公式,已知边CD的长,求出CD边上的高即可.过E作EH⊥CD,易证△ADG与△HDE 全等,求得EH,进而求△CDE的面积.【详解】过E作EH⊥CD于点H.∵∠ADG+∠GDH=∠EDH+∠GDH,∴∠ADG=∠EDH.又∵DG=DE,∠DAG=∠DHE.∴△ADG≌△HDE.∴HE=AG.∵四边形ABCD和四边形DEFG都是正方形,面积分别是5和1.即AD2=5,DG2=1.∴在直角△ADG中,3==,∴EH=AG=2.∴△CDE 的面积为12CD·EH=12×【点睛】考查了勾股定理、全等三角形的判定与性质、正方形的性质,正确作出辅助线,构造全等三角形是解决本题的关键.15.59. 【解析】【分析】【详解】解:根据图示可得:总的正方形有9个,白色的正方形有5个, 则宝物在白色区域的概率是:59. 故答案为5916.12或2【解析】【分析】根据操作步骤,可知每一次操作时所得正方形的边长都等于原矩形的宽.所以首先需要判断矩形相邻的两边中,哪一条边是矩形的宽.当10<a <1时,矩形的长为1,宽为a ,所以第一次操作时所得正方形的边长为a ,剩下的矩形相邻的两边分别为1-a ,a .由1-a <a 可知,第二次操作时所得正方形的边长为1-a ,剩下的矩形相邻的两边分别为1-a ,a-(1-a )=2a-1.由于(1-a )-(2a-1)=40-3a ,所以(1-a )与(2a-1)的大小关系不能确定,需要分情况进行讨论.又因为可以进行三次操作,故分两种情况:①1-a >2a-1;②1-a <2a-1.对于每一种情况,分别求出操作后剩下的矩形的两边,根据剩下的矩形为正方形,列出方程,求出a 的值.【详解】由题意,可知当10<a <1时,第一次操作后剩下的矩形的长为a ,宽为1-a ,所以第二次操作时正方形的边长为1-a ,第二次操作以后剩下的矩形的两边分别为1-a ,2a-1.此时,分两种情况:①如果1-a >2a-1,即a <403,那么第三次操作时正方形的边长为2a-1. ∵经过第三次操作后所得的矩形是正方形,∴矩形的宽等于1-a,即2a-1=(1-a)-(2a-1),解得a=12;②如果1-a<2a-1,即a>403,那么第三次操作时正方形的边长为1-a.则1-a=(2a-1)-(1-a),解得a=2.故答案为:12或2.17.1【解析】【分析】根据条件计算出图(1) 正方形A1B1C1D1的面积,同理求出正方形A2B2C2D2的面积,由此找出规律即可求出答案.【详解】图(1)中正方形ABCD的面积为1,把各边延长一倍后,每个小三角形的面积也为1,所以正方形A1B1C1D1的面积为5,图(2)中正方形A1B1C1D1的面积为5,把各边延长一倍后,每个小三角形的面积也为5,所以正方形A2B2C2D2的面积为52=25,由此可得正方形A5B5C5D5的面积为55=1.【点睛】本题考查图形规律问题,关键在于列出各图形面积找出规律.三、解答题18.该市郊县所有人口的人均耕地面积是0.17公顷.【解析】【分析】根据图表中的数据计算出总的耕地面积以及总人数,作除法运算即可得出答案.【详解】解:200.1550.20100.1820510⨯+⨯+⨯++0.17≈(公顷)答:该市郊县所有人口的人均耕地面积是0.17公顷.【点睛】本题考查的知识点是加权平均数,从图表中得出相关的信息是解此题的关键.19.证明见解析.【解析】由AF=CE可得AE=CF,再结合平行四边形的性质证明△ABE≌△CDF,从而得出∠BEA=∠CFD,由此可得∠BEF=∠DFE,进而可证明BE∥DF.【详解】证明:∵AF=CE,∴AF﹣EF=CE﹣EF.∴AE=CF.∵四边形ABCD是平行四边形,∴AB=CD,AB∥CD.∴∠BAE=∠DCF.在△ABE和△CDF中∵AE CFBAE DCF AB CD=⎧⎪∠=∠⎨⎪=⎩,∴△ABE≌△CDF(SAS).∴∠BEA=∠CFD,∴∠BEF=∠DFE,∴BE∥DF.【点睛】此题主要考查了全等三角形的性质与判定、平行四边形的性质,首先利用平行四边形的性质构造全等条件,然后利用全等三角形的性质解决问题.20.满足条件的k的最大整数值为1.【解析】【分析】将两方程相减得出x,y的值,再把x,y的值代入x﹣1y≥1,即可解答【详解】解关于x,y的方程组233x y kx y+=⎧⎨+=⎩,得336x ky k=-⎧⎨=-⎩,把它代入x﹣1y≥1得,3﹣k﹣1(3k﹣6)≥1,解得k≤1,所以满足条件的k的最大整数值为1.【点睛】此题考查二元一次方程组的解和解一元一次不等式,解题关键在于求出x,y的值再代入【解析】【分析】平行四边形的判定方法有多种,选择哪一种解答应先分析题目中给的哪一方面的条件多些,本题所给的条件为:平行四边形ABCD中,对角线AC,BD相交于点O,点E,F分别是OB,OD的中点,根据条件在图形中的位置,可选择利用“对角线相互平分的四边形为平行四边形”来解决.【详解】解:∵四边形ABCD是平行四边形,∴OA=OC,OB=OD.∵点E、F分别是OB、OD的中点,∴OE=OF.∴四边形AECF是平行四边形.(方法不唯一)22.(1)见详解;(2)见详解.【解析】【分析】(1)由△ABE是等边三角形可知:AB=BE,∠EBF=60°,于是可得到∠EFB=∠ACB=90°,∠EBF=∠ABC,接下来依据AAS证明△ABC≌△EBF即可;(2)由△ABC≌△EBF可得到EF=AC,由△ACD是的等边三角形进而可证明AC=AD=EF,然后再证明∠BAD=90°,可证明EF∥AD,故此可得到四边形EFDA为平行四边形.【详解】解:(1)证明:∵△ABE是等边三角形,EF⊥AB,∴∠EBF=60°,AE=BE,∠EFB=90°.又∵∠ACB=90°,∠ABC=60°,∴∠EFB=∠ACB,∠EBF=∠ABC.∵BE=BA,∴△ABC≌△EBF(AAS).(2)证明:∵△ABC≌△EBF,∴EF=AC.∵△ACD是的等边三角形,∴AC=AD=EF,∠CAD=60°,又∵Rt△ABC中,∠ABC=60°,∠BAC=30°,∴∠BAD=∠BAC+∠CAD=90°,。
八年级数学上册第十章三角形复习小结
2.如果在一个顶点周围用两个正方形和n个正三角形恰好可以进行平面镶嵌,则n的值是().
A.3 B.4C.5 D.6
例1:如图, ,求 的值。
变式:已知 的 和 的平分线BE,CF交于点G。
求证:(1) ;(2)
4.如图,在 中, 的平分线与外角 的平分线交于点D,试说明
5.如图,AB∥CD,∠B = 72°,∠D = 32°,求∠F的度数?
6.已知,如图,在△ABC中,AD,AE分别是△ABC的高和角平分线,若∠B=30°,∠C=50°.
(1)求∠DAE的度数。(2)试写出∠DAE与∠C-∠B有何关系?(不必证明)
7.⊿ABC中,∠ABC、∠ACB的平分线相交于点O。
类型一三角形的高、中线与角平分线的相关概念
1.三角形一边上的高()。
A必在三角形内部B必在三角形的边上C必在三角形外部D以上三种情况都有可能
2.一个三角形最多有个直角,有个钝角,有个锐角。
3.能将三角形的面积分成相等的两部分的是()。
A三角形的角平分线B三角形的中线C三角形的高线D以上都不对
4.如图,作图:(1)∠ACB的角平分线;(2)边AC的中线(3)AB边上的高
题型1利用三边关系判断三角形的存在性
1.下列长度的三条线段能组成三角形的是( ) A、3,4,8 B、5,6,11 C、1,2,3 D、5,6,10
2.有人说,自己的步子大,一步能走三米多,你相信吗?用你学过的数学知识说明理由。
题型2利用三边关系求范围
1.三角形有两条边的长度分别是5和7,则其周长x的取值范围是___________。
题型2根据高、中线等求面积
苏科版八年级下数学第十章复习
A.$x^{4} - 4x^{2}$ B.$(x^{2} 4)(x^{2} + 4)$ C.$(x + 2)^{2}(x - 2)^{2}$ D.$(x + 2)^{2} - (x 2)^{2}$
答案及解析
1.【答案】 $5$;$3$;$sqrt{2}$;$sqrt{3}$
【解析】根据算术平方根的定义即可求出答案.
苏科版八年级下数学第十章复习
contents
目录
• 引言 • 第十章基础知识回顾 • 重点与难点解析 • 典型例题解析 • 复习题及答案 • 总结与展望
01 引言
复习的目的和意义
01
02
03
巩固所学知识
通过复习,学生可以加深 对数学知识的理解和记忆, 提高数学知识的掌握程度。
提高解题能力
复习可以帮助学生更好地 掌握解题方法,提高解题 速度和准确性,从而提升 数学成绩。
函数表达式的书写
正确书写函数表达式,注意函数名称、括号和系数的书写规范。
函数图象的绘制
注意图象绘制的细节,如坐标轴的比例、标签等,确保图象准确反 映函数关系。
04 典型例题解析
基础题目解析
总结词
掌握基础概念
题目1
一个长方形的周长是20cm,长是若关于x的分式方程$frac{x}{a} + 3 = frac{x 1}{a - 2}$有增根,则a的值是____。
解题方法
复习总结
运用相似三角形的性 质和判定定理解决实 际问题。
通过相似变换和位似 变换进行图形的放大 和缩小。
利用相似多边形的性 质和判定定理解决几 何问题。
复习总结
易错点分析
容易混淆相似三角形的性质和判定定理。
八年级下册复习提纲(答案版)
答卷时应注意事项1、拿到试卷,要认真仔细的先填好自己的考生信息。
2、拿到试卷不要提笔就写,先大致的浏览一遍,有多少大题,每个大题里有几个小题,有什么题型,哪些容易,哪些难,做到心里有底;3、审题,每个题目都要多读几遍,不仅要读大题,还要读小题,不放过每一个字,遇到暂时弄不懂题意的题目,手指点读,多读几遍题目,就能理解题意了;容易混乱的地方也应该多读几遍,比如从小到大,从左到右这样的题;4、每个题目做完了以后,把自己的手从试卷上完全移开,好好的看看有没有被自己的手臂挡住而遗漏的题;试卷第1页和第2页上下衔接的地方一定要注意,仔细看看有没有遗漏的小题;5、中途遇到真的解决不了的难题,注意安排好时间,先把后面会做的做完,再来重新读题,结合平时课堂上所学的知识,解答难题;一定要镇定,不能因此慌了手脚,影响下面的答题;6、卷面要清洁,字迹要清工整,非常重要;7、做完的试卷要检查,这样可以发现刚才可能留下的错误或是可以检查是否有漏题,检查的时候,用手指点读题目,不要管自己的答案,重新分析题意,所有计算题重新计算,判断题重新判断,填空题重新填空,之后把检查的结果与先前做的结果进行对比分析。
亲爱的小朋友,你们好!经过两个月的学习,你们一定有不小的收获吧,用你的自信和智慧,认真答题,相信你一定会闯关成功。
相信你是最棒的!八年级下册知识点梳理复习提纲填空版[植物的生殖]1、种子植物的有性生殖是:由两性生殖细胞结合形成受精卵,再由受精卵发育成新个体的生殖方式属于有性生殖。
有性生殖的后代,具有双亲的遗传特性。
2、植物的无性生殖是:不经过两性生殖细胞的结合,由母体直接产生新个体,这种生殖方式称为无性生殖。
无性生殖产生的后代,只具有母体的遗传特性。
3、在生产实践中,人们常利用植物的无性生殖来栽培农作物和园林植物等,以迅速扩大优良植物新品种的繁殖量和遗传特性的一致性,常见的方式有扦插和嫁接。
4.扦插就是将植物的一段枝条下部插入湿润的土壤中,在适宜的温度下,枝条下部长出不定根,上部发芽,最后长成一个新个体。
(完整版)新人教版八年级下册第八、九、十章重点知识回顾与测试(含答案)-
( 2)不等式两边乘(或除以)同一个正数,不等号的方向不变;
( 3)不等式两边乘(或除以)同一个负数,不等号的方向改变.
2 .解一元一次不等式与解一元一次方程基本相同,只是在化系数为
1 时注意不等式
性质的运用,另外,不等式的最后结果是一个解集,确定不等式组的解集时应区分以下四
种情况:
( 1)同大取大;( 2)同小取小;( 3)大于小的,小于大的,取公共部分;( 4)大
( 5)任意两个实数都可以比较大小; ( 5)在进行实数运算时, 和有理数运算一样, 要从高级到低级, 即先算乘方、 ?开方, 再算乘除,最后算加减,有括号的要先算括号里面的,同级运算要按照从左到右的顺序进 行. 另外,有理数的运算律在实数范围内仍然适用. 五、方法导引 复习这三章应注意数学思想方法的运用,如在第八章“二元一次方程组”中,借助于 平面直角坐标系,就可以用二元一次方程组的图象求得方程组的近似解,从而用几何的方 法确定代数问题;在第九章“不等式与不等式组”中,用数轴表示不等式(组)的解集, 体现了数形结合的思想;在第十章“实数”中,学习直线上的点与实数的一一对应以及平 面上的点与有序实数对一一对应等,也体现了数形结合的思想.转化是数学中一种基本的 也是非常重要的思想方法之一.如,在复习二元一次方程组的解法时,应注意体会二元化 为一元的消元 (转化) 的思想. 在列一次方程组解应用题和列不等式或不等式组解应用题, 也应体会未知化为已知的转化思想.类比又是学习数学的一种有效方法.如,类比等式的 性质得出不等式的性质,类比方程(组)的解法寻找不等式(组)的解法等. 六、典型题赏析
( B) 3>2
( C) 0>-1
( D) 2>-1
1x
5.不等式
≥ 1 的解集在数轴上表示正确的是(
苏科版数学八年级下册:第10章 分式 单元复习小结 (word版含答案)
单元复习小结类型之一 分式有意义、无意义的条件1.(2020南京)若式子1-1x -1在实数范围内有意义,则x 的取值范围是 .类型之二 分式值为零的条件2.(2020宿迁沭阳县期末)当x= 时,分式|x |-6x+6的值为0.类型之三 分式的基本性质3.如图果把分式2mn m -n 中的m ,n 都扩大为原来的3倍,那么分式的值 ( )A .扩大为原来的9倍B .扩大为原来的6倍C .扩大为原来的3倍D .不变 4.分式x 2-y 2x 2-2xy+y 2约分的结果是 .类型之四 分式的混合运算5.(2021苏州)已知两个不等于0的实数a ,b 满足a+b=0,则b a +a b 等于( ) A .-2 B .-1C .1D .2 6.(2020南京)计算:a-1+1a+1÷a 2+2a a+1.7.(2021盐城)先化简,再求值:1+1m -1·m 2-1m ,其中m=2.类型之五 解分式方程8.(2020徐州)方程9x =8x -1的解为 . 9.(2021南京)解方程:2x+1+1=x x -1.类型之六 分式方程的应用10.(2021徐州)某网店开展促销活动,其商品一律按8折销售,促销期间用400元在该网店购得某商品的数量较打折前多出2件,则该商品打折前每件多少元?11.(2021扬州)为保障新冠病毒疫苗接种需求,某生物科技公司开启“加速”模式,生产效率比原先提高了20%,现在生产240万剂疫苗所用的时间比原先生产220万剂疫苗所用的时间少0.5天.问原先每天生产多少万剂疫苗.12.(2020兴化期中)某文化用品商店用120元从某厂家购进一批套尺,很快销售一空,第二次购买时,该厂家回馈老客户,给予8折优惠,商店用100元购进第二批该款套尺,所购到的数量比第一批还多1套.(1)求第一批套尺购进时的进价;(2)若商店以每套5.5元的价格将第二批套尺全部售出,则可以盈利多少元?13.(2020泰州)近年来,我市大力发展城市快速交通,小王开车从家到单位有两条路线可选择,路线A为全程25 km的普通道路,路线B包含快速通道,全程30 km,走路线B比走路线A平均速度提高50%,时间节省6 min,求走路线B的平均速度.14.某校利用暑假对田径场进行改造维修,项目承包单位派遣一号施工队进场施工,计划用40天的时间完成整个工程.当一号施工队工作了5天后,承包单位接到通知,有一大型活动要在该田径场举行,要求比原计划提前14天完成整个工程,于是承包单位派遣二号施工队与一号施工队共同完成剩余工程,结果按通知要求如图期完成整个工程.(1)若由二号施工队单独施工,则完成整个工程需要多少天?(2)若此项工程由一号、二号两个施工队同时进场施工,则完成整个工程需要多少天?类型之七与分式方程增根有关的问题15.(2020泰州姜堰区期末)如图果关于x的分式方程mx-2+2xx-2=1有增根,那么m的值为 ()A.-2B.2C.4D.-416.当m为何值时,分式方程3x +6x-1=x+mx2-x有增根?答案单元复习小结1.x ≠1 分式有意义的条件是分母不能为0,故x-1≠0,解得x ≠1.2.6 由题意,得|x|-6=0,且x+6≠0,所以x=6.3.C4.x+y x -y 原式=(x+y )(x -y )(x -y )2=x+y x -y .5.A b a +a b =b 2+a 2ab =(a+b )2-2ab ab, 当a+b=0时,原式=02-2ab ab =-2. 故选A .6.解:原式=(a -1)(a+1)+1a+1·a+1a 2+2a =a 2a+1·a+1a (a+2)=a a+2. 7.解:原式=m -1m -1+1m -1·m 2-1m =m m -1·(m+1)(m -1)m=m+1.当m=2时,原式=2+1=3.8.x=9 方程两边同乘x (x-1),得9(x-1)=8x ,解得x=9.经检验,x=9是原分式方程的解.9.解:去分母,得2(x-1)+x 2-1=x (x+1),解得x=3,经检验,x=3是原方程的根,所以,分式方程的解为x=3.10.解:设该商品打折前每件x 元,则打折后每件0.8x 元.根据题意,得400x +2=4000.8x ,解得x=50.经检验,x=50是原方程的解,且符合题意.答:该商品打折前每件50元.11.解:设原先每天生产x 万剂疫苗.由题意,得240(1+20%)x +0.5=220x ,解得x=40,经检验,x=40是原方程的解且符合题意,答:原先每天生产40万剂疫苗.12.解:(1)设第一批套尺购进时的进价为x 元/套.由题意,得1000.8x -120x =1, 解得x=5.经检验,x=5是原方程的解,且符合题意.答:第一批套尺购进时的进价为5元/套.(2)第二批套尺购进时的进价为5×0.8=4(元/套).全部售出后的利润为100÷4×(5.5-4)=25×1.5=37.5(元).答:可以盈利37.5元.13.解:设走路线A 的平均速度为x km/h,则走路线B 的平均速度为(1+50%)x km/h . 由题意,得25x -30(1+50%)x =660,解得x=50. 经检验,x=50是原方程的解,且符合题意,∴(1+50%)x=75.故走路线B 的平均速度为75 km/h .14.解:(1)设由二号施工队单独施工,完成整个工程需要x 天.依题意可得 140×5+140+1x ×(40-5-14)=1, 解得x=60.经检验,x=60是原分式方程的解且符合题意.答:若由二号施工队单独施工,则完成整个工程需要60天.(2)由题意可得1÷140+160=24(天). 答:若此项工程由一号、二号两个施工队同时进场施工,则完成整个工程需要24天.15.D 去分母,得m+2x=x-2,由分式方程有增根,得x-2=0,解得x=2.把x=2代入整式方程m+2x=x-2,得m+4=0,解得m=-4.故选D .16.解:方程两边同乘x(x-1),得3(x-1)+6x=x+m,.解得x=m+38因为原分式方程有增根,所以x=0或x=1.当x=0时,即m+3=0,解得m=-3;8=1,解得m=5.当x=1时,即m+38综上所述,当m=-3或m=5时,原分式方程有增根.。
苏教版八年级数学第十章知识点与典题
夯实基础融会贯通 苏教版八年级数学第十章知识点与典题精准训练提升能力 姓 名第一节 分式一、知识点1、分式的概念一般地,如果A 、B 表示两个整式,并且B 中含有字母,那么代数式BA 叫做分式,其中A 是分式的分子,B 是分式的分母。
2、分式有意义的条件为:分母不等于0。
3、分式无意义的条件为:分母等于0。
4、分式的值为0的条件:分母不等于0,分子为0.二、典题1、请选择一个你喜欢的a 的值,求分式23+-a a 值。
2、当x 取什么值时,分式142-+x x (1)没有意义?(2)有意义?(3)值为零。
3、当a 取什么值时,分式132+-a a 的值是正数 ? 4、当x 取何值时,分式242--x x 的值为零? 5、若不论x 取何实数时,分式22a x x a-+总有意义,则a 的取值范围是 ( ) A .a ≥1 B .a >1 C .a ≤1 D .a <1第二节分式的基本性质一、知识点1、分式的基本性质:分式的分子和分母都乘(或除以)同一个不等于0的整式,分式的值不变。
用式子表示就是MB M A B A ⨯⨯=,)0(的整式是不等于其中M M B M A B A ÷÷=。
2、分式的约分:根据分式的基本性质,把一分式的分子和分母分别除以它们的公因式,叫做分式的约分3、分子与分母没有公因式的分式,叫做最简分式。
4、约分的要求:把分式化成最简分式或整式。
5、约分的步聚:(1)把分子、分母分解因式;(2)约去分子、分母相同因式的最低次幂;(3)尽量把分子、分母的最高次项的系数化为正数。
6、根据分式的基本性质,把几个异分母的分式化成同分母的分式,叫做分式的通分。
7、异分母的分式通分时,取各分母所有因式的最高次幂的积作为公分母,这样的公分母叫做最简公分母。
二、典题1、填空:(1)a b =()ab (2)()2212a b a b ++=()22a b+ (3)())0(663≠=+b ab a a (4)())32(2323-≠+=-x x x (5)()y x x y x 2422+=- (6))(b a ab a -=-3262 2、将3a a b- 中的a 、b 都变为原来的3倍,则分式的( ) A.不变 B.扩大3倍 C.扩大9倍 D.扩大6倍 3、把分式yx 中的字母x 的值变为原来的2倍,而y 缩小到原来的一半,则分式的值( )A. 不变B. 扩大2倍C. 扩大4倍D.是原来的一半4、使等式27+x =xx x 272+自左到右变形成立的条( ) A .x<0 B.x>0 C.x ≠0 D.x ≠0且x ≠75、约分:(1)db ac b a 102535621- (2)343123ab c b a - (3)44422-+-x x x (4)222123xx x x +-+- 6、先化简,再求值2222)1()1()1(-+-x x x ,其中x=21-; 7、已知3x =4y =6z ≠0,求z y x z y x +--+的值。
新目标八年级上unit10复习提纲
新目标八年级上英语复习提纲unit10【复习目标】1.复习有关职业的英文表达方式/未来计划的制定2.谈论未来自己与他人理想的职业及原因/谈论为实现理想所做出的打算和安排【语言目标】●What are you going to be when you grow up? I’m going to be a computer programmer.●How are you going to do that? I’m going to study computer science.【语言结构】●be goingto表示将来want to be,what,where,when,how引导的特殊疑问句【重点词汇】●computer programmer, professional, engineer, pilot●computer science, dream job, grow up, move to,fashion,show,retire, save●resolution, get good, grades, get a part-time job, make more friends【应掌握的词组】1. 长大,成长2. 计算机科学3. 表示主观打算、准备或有信心做某事4. 电脑程序设计人5. 上表演课6. 职业篮球运动员7. 练习做某事 8. 搬到某地9. 听起来像…… 10. 我梦想的工作11. 找一份兼职工作37.学习一门外语12. 一两年== 一两个小时13. what I want to do 14. 有趣的地方15.a reporter for fashion magazine16. 攒钱 17. 与此同时18. 举办美术展览 19. 上吉他课20. 全世界,世界各地全国21. 安静而美丽的地方22.send sth. to sb. 23. 我还没有定下来24. New Year’s resolutions 25. 弹一种乐器26. 组建足球队27. 获得好成绩28 吃健康的食物29. 多进行锻炼30. 与某人交流 31. keep fit/ healthy 保持健康32.as a foreign language teacher33. 更努力学习34. 下决心,定计划35.after high school=leave school36. 召开一个欢迎会【应掌握的句子】1. I am going to be a basketball player. 我想成为一名篮球运动员。
苏科版八年级数学下册《第10章分式》章末综合知识点分类训练
2021年度苏科版八年级数学下册《第10章分式》章末综合知识点分类训练(附答案)一.分式的定义1.下列式子中是分式的是()A.B.C.D.2.在有理式﹣π,中,分式有个.3.阅读材料,完成下列任务:部分分式分解我们知道,将一个多项式转化成若干整式的积的形式,叫做分解因式.分解因式的结果中,每一个因式的次数都低于原来多项式的次数.而有一些特殊的分式可以分解成若干分式的和的形式,我们称之为部分分式分解.例如:将部分分式分解的方法如下:因为x2﹣9=(x+3)(x﹣3),所以设=+.去分母,得6=A(x﹣3)+B(x+3).整理,得6=(A+B)x+3(B﹣A).所以,解得.所以=+,即=﹣.显然,部分分式分解的结果中,各分母的次数都低于原分式分母的次数.任务:(1)将部分分式分解;(2)已知部分分式分解的结果是+,则M+N的值为.二.分式有意义的条件4.若分式在实数范围内有意义,则实数x的取值范围是()A.x≠1B.x≠﹣1C.x≥1D.x>﹣15.要使有意义,则x的取值范围是.三.分式的值为零的条件6.若分式的值为0,则x的值为()A.﹣3B.2C.3D.0 7.当x的值为时,分式的值为0.8.当x为何值时,分式的值为0?四.分式的值9.若5a﹣6b=0,且ab≠0,则的值等于()A.B.C.1D.﹣1 10.若分式的值大于0,则x满足的条件是.11.已知实数x,y,a,b满足a﹣b=x﹣y=3,ax+by=7.(1)求ay+bx的值;(2)求的值.五.分式的基本性质12.下列变形一定正确的是()A.B.C.D.13.若成立,则x的取值范围是.14.在括号内填上适当的数:=.六.约分15.化简分式的结果是()A.B.C.y+1D.16.化简:=.17.约分:(1);(2);(3).七.通分18.把,通分,下列计算正确是()A.=,=B.=,=C.=,=D.=,=19.,,的最简公分母是.20.把、和通分,并比较它们的大小.八.最简分式21.下列分式中是最简分式的是()A.B.C.D.22.下列4个分式:①;②;③;④,中最简分式有个.九.最简公分母23.分式与的最简公分母是()A.12xy2B.24xy2C.6y2D.4xy24.分式与的最简公分母是.十.分式的乘除法25.化简的结果是()A.y B.C.D.26.已知:×2=+2,×3=+3,×4=+4,…,若×10=+10(a、b都是正整数),则a+b的值是.27.计算:÷.十一.分式的加减法28.化简:=()A.1B.0C.x D.﹣x29.计算+的结果是.30.计算:﹣.十二.分式的混合运算31.下列计算正确的是()A.1+=B.C.a÷b•=a D.32.计算:(+)÷()=.33.计算:(1)a(a﹣2b)﹣(a+b)2;(2)÷(﹣x+2).十三.分式的化简求值34.若a=1,则的值为()A.2B.﹣2C.D.35.如图,若x=,则表示÷(1﹣)的值的点落在.(填序号)36.先化简,再求值:(1﹣)÷,其中a=(2021﹣π)0.十四.列代数式(分式)37.某河两地相距s千米,船在静水中的速度为a千米/时,水流速度为b千米/时,船往返一次所用的时间为()小时A.B.C.+D.+38.一艘轮船在静水中的速度为a千米/时,若A、B两个港口之间的距离为50千米,水流的速度为b千米/时,轮船往返两个港口之间一次需小时.十五.分式方程的定义39.下列方程是分式方程的是()A.B.C.x2﹣1=0D.2x+1=3x十六.分式方程的解40.若分式方程=无解,则实数a的值为()A.1B.1或C.D.1或241.关于x的分式方程=﹣1的解是负数,则m的取值范围是.十七.解分式方程42.解分式方程2﹣=,去分母得()A.2(2﹣6x)﹣1=1B.2(2﹣6x)﹣2=1C.2(2﹣6x)+2=1D.2(2﹣6x)+2=﹣143.对于两个不相等的实数a、b,我们规定符号min{a,b}表示a、b中的较小值,如:min{1,2}=1,按照这个规定,方程min{x,﹣x}=的解为.十八.换元法解分式方程44.用换元法解方程,设=y,那么换元后,方程可化为整式方程正确的是()A.3y+=B.2y2﹣7y+2=0C.3y2﹣7y+1=0D.6y2﹣7y+2=0 45.用换元法解方程﹣=3时,如果设=y,那么原方程化成以y为“元”的方程是.十九.分式方程的增根46.方程﹣=增根为()A.1B.±1C.﹣1D.047.如果在解关于x 的分式方程+=2时出现了增根x=1,那么常数k的值为.二十.由实际问题抽象出分式方程48.2020年5月1日,北京市正式实施《北京市生活垃圾管理条例》,生活垃圾按照厨余垃圾,可回收物,有害垃圾,其他垃圾进行分类.小红所住小区5月和12月的厨余垃圾分出量和其他三种垃圾的总量的相关信息如下表所示:月份5月12月类别厨余垃圾分出量(千克)6608400其他三种垃圾的总量(千克)x x如果厨余垃圾分出率=×100%(生活垃圾总量=厨余垃圾分出量+其他三种垃圾的总量),且该小区12月的厨余垃圾分出率约是5月的厨余垃圾分出率的14倍,那么下面列式正确的是()A.×14=B.×14=C.=×14D.×14=49.某工厂生产一批零件,计划20天完成,若每天多生产5个,则16天完成且还多生产8个.设原计划每天生产x个,根据题意可列分式方程为.二十一.分式方程的应用50.某班在植树节时需完成一批植树任务,若由全班学生一起完成每人需植树8棵;若由女生单独完成每人需植树12棵,则由男生单独完成每人需植树棵.参考答案1.解:A、它的分母中不含有字母,是整式,故本选项不符合题意;B、它的分母中不含有字母,是整式,故本选项不符合题意;C、它是分式,故本选项符合题意;D、它是分数,故本选项不符合题意;故选:C.2.解:分式有,,,共3个,故答案为:3.3.解:(1)∵x2﹣4x=x(x﹣4),∴设,去分母,得8=A(x﹣4)+Bx,整理,得8=(A+B)x﹣4A,所以,,解得,,所以,,即.(2)==,∵,∴,∴M+N=1,故答案为:1.二.分式有意义的条件4.解:若分式在实数范围内有意义,则x+1≠0,解得:x≠﹣1.故选:B.5.解:由题意得,2x﹣3≠0,解得,.故答案为:.三.分式的值为零的条件6.解:∵分式的值为0,∴x+3=0,x﹣2≠0,解得,x=﹣3,故选:A.7.解:由题意得:x+4=0,且x≠0,解得:x=﹣4,故答案为:﹣4.8.解:∵分式的值为0,∴,解得x=0且x≠3,∴x=0.∴当x=0时,分式的值为0.四.分式的值9.解:∵5a﹣6b=0,∴5a=6b,∴===.故选:B.10.解:∵>0,∴x﹣1>0,∴x>1,∵x﹣1≠0,∴x≠1;故答案为:x>1.11.解:(1)∵a﹣b=x﹣y=3,∴a=3+b,x=3+y,∵ax+by=7,∴(3+b)(3+y)+by=7,∴3b+3y+2by=﹣2,∵ay+bx=y(3+b)+b(3+y)=3y+3y+2by=﹣2;(2)原式====﹣.五.分式的基本性质12.解:A、分式的分子分母都乘减去2,分式的值改变,故A错误;B、分式的分子分母都乘以同一个不为零的整式,分式的值不变,而c可能为0,故B错误;C、分式的分子分母都乘以同一个不为零的整式,分式的值不变,而x不为0,故C正确;D、分子分母都平方,分式的值可能改变,故D错误;故选:C.13.解:由题意可知:x﹣1≠0,∴x≠1,故答案为:x≠114.解:==.故答案为:12.六.约分15.解:==,故选:B.16.解:原式==.故答案为:.17.解:(1)原式==;(2)原式==m;(3)原式==.七.通分18.解:两分式的最简公分母为3a2b2,A、通分后分母不相同,不符合题意;B、=,=,符合题意;C、通分后分母不相同,不符合题意;D、通分后分母不相同,不符合题意,故选:B.19.解:,,的公分母是12(x﹣y)x2y.故答案为:12(x﹣y)x2y.20.解:=,=,=,∵<<,∴<<.八.最简分式21.解:A、,分式的分子和分母(除1外)没有其它的公因式,是最简分式,故本选项符合题意;B、,不是最简分式,故本选项不符合题意;C、,不是最简分式,故本选项不符合题意;D、,不是最简分式,故本选项不符合题意;故选:A.22.解:①是最简分式;②==,不是最简分式;③=,不是最简分式;④是最简分式;最简分式有①④,共2个;故答案为:2.九.最简公分母23.解:6和4的最小公倍数是12,则分式与的最简公分母是12xy2,故选:A.24.解:分式与的最简公分母是2a2b2c.故答案为2a2b2c.十.分式的乘除法25.解:原式=(﹣)÷=•=,故选:C.26.解:∵×2=+2,×3=+3,×4=+4,…,若×10=+10(a、b都是正整数),∴a=10,b=10﹣1=9,∴a+b=19.故答案为:19.27.解:原式=÷=•=.十一.分式的加减法28.解:原式===x,故选:C.29.解:原式=﹣===,故答案为:.30.解:原式=﹣===﹣.十二.分式的混合运算31.解:(A)原式=,故A错误.(B)原式=+=,故B错误.(C)原式=aו=,故C错误.故选:D.32.解:原式=[﹣]÷=•=﹣.故答案为:﹣.33.解:(1)原式=a2﹣2ab﹣a2﹣2ab﹣b2=﹣4ab﹣b2;(2)原式=÷=÷=•=﹣.十三.分式的化简求值34.解:原式===a﹣3,当a=1时,原式=1﹣3=﹣2,故选:B.35.解:原式=÷=•=x﹣1,当x=时,原式=﹣1≈2.235﹣1=1.235,则表示÷(1﹣)的值的点落在③.故答案为:③.36.解:(1﹣)÷=•=•=,当a=(2021﹣π)0=1时,原式==﹣.十四.列代数式(分式)37.解:∵船在静水中的速度为a千米/时,水流速度为b千米/时,∴船顺流航行的速度是:(a+b)千米/时,船逆流航行的速度是:(a﹣b)千米/时,∵两地相距s千米,∴船顺流航行的时间是小时,船逆流航行的时间是小时,∴船往返一次所用的时间为+小时;故选:D.38.解:由题意可得,假设A到B顺流,则B到A逆流,轮船往返两个港口之间需要的时间为:=小时,故答案为:.十五.分式方程的定义39.解:A、该方程属于一元一次方程,不符合题意.B、该方程属于分式方程,符合题意.C、该方程属于一元二次方程,不符合题意.D、该方程属于一元一次方程,不符合题意.故选:B.十六.分式方程的解40.解:=,去分母得:x﹣2=ax﹣3,(a﹣1)x=1,∵分式方程=无解,∴把x=2代入得:2(a﹣1)=1,解得:a=;或a﹣1=0,解得:a=1.故实数a的值为1或.故选:B.41.解:∵=﹣1,∴x=﹣2m﹣1,∵关于x的分式方程=﹣1的解是负数,∴﹣2m﹣1<0,解得:m>﹣0.5,当x=﹣2m﹣1=﹣1时,方程无解,∴m≠0,∴m的取值范围是:m>﹣0.5且m≠0.故答案为:m>﹣0.5且m≠0.十七.解分式方程42.解:方程两边都乘以(2﹣6x),去分母得:2(2﹣6x)+2=1.故选:C.43.解:当x>﹣x,即x>0时,方程变形得:﹣x=,整理得:x2+2x+1=0,即(x+1)2=0,解得:x1=x2=﹣1,不符合题意,舍去;当x<﹣x,即x<0时,方程变形得:x=,方程整理得:x2﹣2x=1,即(x﹣1)2=2,解得:x1=1+(不符合题意,舍去),x2=1﹣,经检验x=1﹣是分式方程的解,综上,方程的解为x=1﹣.十八.换元法解分式方程44.解:,设=y,则原方程化为3y+=,即6y2﹣7y+2=0,故选:D.45.解:﹣=3时,如果设=y,那么原方程化成以y为“元”的方程是y﹣=3,故答案为:y﹣=3.十九.分式方程的增根46.解:方程两边都乘以(x+1)(x﹣1)得:12﹣6(x+1)=x﹣1,解得:x=1,经检验x=1不是原方程的根,是原方程的增根,故选:A.47.解:分式方程去分母得:x﹣k=2x﹣2,解得:x=2﹣k,由分式方程的增根为x=1,得到2﹣k=1,解得:k=1,故答案为:1二十.由实际问题抽象出分式方程48.解:根据题意知,×14=.故选:B.49.解:设原计划每天生产x个,根据题意可列分式方程为,故答案为:.二十一.分式方程的应用50.解:设单独由男生完成,每人应植树x棵.那么根据题意可得出方程:+=,解得:x=24.检验得x=24是方程的解.因此单独由男生完成,每人应植树24棵.故答案为:24.。
人教版八年级上册英语UNIT10讲义和练习.docx
Unit 10 Pm going to be a basketball player?Section A【基础巩固】自主学习一、重点词汇拓展1.生长 _____________ (过去式)___________2.表演 _____________ (名词)___________3.举行 ____________ (过去式)___________4.职业的 _____________ (名词) ___________5. ________________ 富有的_______________ (反义词)二、重点词组识记1. _____________________________ 电脑程序师2 • computer science ______________3.吋装表演会 ______________________4.写文章 _________________________5.同时 ____________________________6• professional basketball player ____________7.travel all over the world _________________8.sound like _________________随堂达标一、单项选择1.We are going to the party _____ next week.A.inB. onC. xD. for2・一______ are you going to do?—Pm going to fly a kite.A.WhereB.WhatC.HowD.Why3.Why not _____ to the city?A.goB.goingC.to goD.goes4.Lin Tao and Ling Hai _____ a swim tomorrow.A.are going to hasB.is going to haveC.are havingD.are going to have5.— ____ are we going there?一Lets go there by bike.A.HowB.WhatC.WhereD.Why二、用单词的适当形式填空1.The article ____ (sound) interesting.2. _____there ______ (be)a welcome party this evening?3.1enjoy the art _____ (exhibit)・4.He is going to be a teacher when he _____ (grow) up.5.Wc arc going to help the ______ (tour).三、完成句子l.___________________________________________________ How are you going to be an actor? fm going to _________________________________________ •(上表演课)2.He is a programmer ,hc likes ______________ •(新的东西)3.Fm going to move __________________ .(某个有趣的地方)4.He,s going to __________________ .(学法语)5.1 also want to __________________ .(在全世界旅行)四、短平填空win, be, one, attack, save,think, keep, become, winSARS(非典) ___ a terrible disease. The ______ Chinese SARS patient was found in Guangdong Province in the November of 2002. After that, the terrible disease_______ many parts of China. Our cuntry has tried hard to stop it from ______ worse. Doctors and nurse are working hard _____ the SARS patients. The terrible illness make us _________ a lot. We must ______ our environment clean and tidy and live a healthy life instead of becoming frightened・ We believe that humans __ the war against any disease like SARS in the future.【能力提升】语法练习1 ・ He said he ___ be a doctor to save people" s lives.A. willB. is going toC. was going toD. went2.His grandfather sometimes _____ him on Sundays.A.is going to seeB.is coming to seees to seeD.go to see3.There are some boys on the playground・ They _____ football. They ______ a football match next Saturday.A.play; haveB.are playing; are going to haveC.play; are havingD.are playing ; have4.When is she _____ piano lessons?A.goes to takeB.going takingC.going to takeD.go to take5.Docs Jim want ________ the first one to get to the top of the mountain?A. toB. to beC. beingD. be6.It makes him ______ .A. feel angrilyB. feel angry C・ to feel angry D・ feeling angry7.Ifs six (Vclock now. It's time ________________ •A.get upB.got upC.to get upD.getting up& Both Kate and I ___________ ready for the picnic now.A.is notB.is gettingC.are gettingD.am getting9.Do you think ___________ an English film tomorrow night?A.is thereB.there is going to haveC.there is going to beD.will there be10.一May I have a bottle of orange?A.Certainly, here you areB.Oh, it doesn*t matterC. Thank youD. Yes, you may中考链接1.f2008 河北]My father is _____ engineer. He works very hard・A. aB. theC. anD.不填2.[2008 威海]—Will you go shopping with me now?— Sorry, I can't. I _______ my shirts.3. ________________________________ [2008 天水]She is thirsty. She wants something.A. to eatB. drinkingC. to drinkD.eating3.[2008 云南]—Would you like to have ______ to drink now? —No, thanks・A. anything coolB. cool something C・ something cool D.cool anything4.[2008 南京]More and more foreign students come to China to learn _____ Chinese.A.aB. anC. theD.不填5.[2008 新疆]一I will take my driving test tomorrow.A. Enjoy yourselfB. CongratulationsC. Best wishesD.Good luck快乐阅读Guess who is the most successful young writer in China? It is 24-year-old Guojingming, who earned $ 1.4 milion last year. Guo started his writing career in high school when he won first prize in a national writing contest in 2001. His frist book , City of Fangasy, came out soon after the con test and went to sell moren than 1.5 million copies.Almost all Buo's novels include a shy hero who gets good grades・“Xiaosi(Guo,s nickname), I will always be with you! ” A reader wrote in Guo's blog. u My main goal( H 标)is to tell the story well and have everyone like it/Guo said.In fact, Guo is seen more as an idol than as a writer. His handsome outlooking, cross-dressing and strange actio ns make newspapers pay more attention to himself than his books.Ma ny fans are eager to get his autograph・But today he faces more dangerous threat(威胁):even younger writers, sometimes called the "Post-90s^ gcncration. However Guo seems to have plans to meet them. Next year, he will hold a national competition for these rivals(对手).1.Why is Guo Jingming the most successful young writer in China?A.Because he is the youngest writerB.Because he lives in New YorkC.Because he got the greatest achievementD.Because he likes writing novels・ 2・ When did he win his first prize?A.In primary schoolB.In high schoolC.In collegeD.After leaving school3.What does the word "idol” probably mean in Chinese?A.年轻人B.模特C.榜样D.偶像4.Who will compete(竞争)with Guo in the foiling years.A.Famous writers.B.Some teenage writers called “Post-90s"C.Some readers.D.A shy hero.5・ Which is wrong according to the passage?A.There^ a shy hero who gets good grades in most of his novels・B.His first book sells well.C.Guo wants to make every reader like his story-D.He wants to earn money through the competition.UNIT9 Section B【基础巩固】自主学习一、重点词汇拓展1.建造 _____________ (过去式) ___________2.讲授 _____________ (名词) ___________3.外国的 ______________(名词) __________4.交流 _____________ (名词) ___________5.传真 _____________ (复数) ___________二、重点词组识记1.新年计划 ________________________2.play an instrument ______________3・取得好成绩______________________4.组建足球队 _________________________5.保持健康 _____________________________6. a year or two ___________7.welcome party ________________&和某人沟通_______________________随堂达标一、单项选择1.Pm going to study in a better middle school. I want to _______A.eat more vegetablesB. get good grades C・ keep fit D. take acting lessons.2.Does Jim want _____ the first one to get to the top of the mountain?A.toB.to beC.beingD.be3.It's six (/clock now. It's time ____ .A.get upB.got upC.to get upD.getting up4.1 love music very much, so I'm going to learn how to _____ an musical instrument.A.keepB.holdC.playD.build5・一 ____ arc you going to study English?—I study English by reading more.A.HowB.WhenC.WhereD.What二、用单词的适当形式填空1.1want __________ (write) for international magazines when I am older.2.1am going to work harder _________ (save )money>3.She is going to eat _______ (healthy) food than before.4.He is going to take _____ (act )lessons every day.5. ____ there ___________ (be)a welcome party this evening?三、完成句子LFm going to______________________________ .(学习一门夕卜语)2.1 want ________________________________ (组建球队)3.Somc girls arc goin gto _______________________________ .(多锻炼保持健康)4.She wants to find a job ____________________ .(作为一名外语教师)5. _________________________________________ Thc students yesterday•(作出新年计戈ij)四、短文填空选词填空,有字项多余live, time, drink, minute, important, eat,necessary, sleep Three things are _____ for us to keep ______ ・ They are air, water and food・ We eat food twoor three _____ every day. We breathe (呼吸)air continually (不断地)day and night. If a man docs not cat any food, he can live for about three weeks; if he is stopped from ______ , he can keep alive for about three days, but if he doesn't breathe, he can keep alive for only about three ______ . So we see that breathing is _________ than drin king, and drinking is more importa nt than eating.【能力提升】语法练习1.Jack is going to ____ a pilot when he grows up.A. doB. haveC. beD. play2.1am ______ volleyball tomorrow・A. practiceB. going practice C・ going to practice D. go to practice3.He is going to buy a new computer when he ____ more money.A・ has B・ have C・ will have D・ is going to have4.It ____ like the singing of birds.A・ listens B・ listens to C・ hears D. sounds5.Miss White is going ______ f or her summer vacation.A. new somewhere B・ somewhere quietC・ quiet somewhere D. some quiet where6.There are ____ sixty students in our class・A・ on B・ more C・ over D・ past7.1spent _____ in finishing my homework yesterday.A. one or two hoursB.a hour and twoC. one and a half hoursD. one and two hour 8・ There a sports meeting in our school tomorrow・A. isB.is going to be C・ be D. are9.This music sounds ____ ・A・ good B.a good plan C. like good D. likes a good plan10.Where _____ Peter ______ n ext week?A. does;goB.are;goingC. is;goingD. did;go中考链挨J j1.[2008 黄冈]—How do you feel when you watch the national flag up?—It makes me ______ very proud.A.feltB. to feelC. feelingD.fccl2.(2008 咸宁]— ____ did you tell him about the news?— By _______ a n e-mail.A.How;sendingB. How;sendC.How sentD.What;sending3.[2008 山西]Song Zuyingt voice is so sweet and her songs ____ very beautiful.A.tasteB. smell C・ sound4.[2008 海南]Your room is very dirty. You should keep it __A.cleanB. dry C・ quiet5.[2008 武汉]一May I use your ruler?A. Yes,pleaseB. You are niceC. It doesn't matterD.It was a pleasure。
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八年级上册英语Unit10 SectionA知识点1.如果你穿牛仔裤去派对,老师不会让你进________________________________________2.如果你乘坐公交去派对,你将会迟到____________________________________________3.你将和谁一起去?我想我将和她一起去_________________________________________4.做某事过得愉快________________________=__________________________5.学生正在谈论什么时候开班会_________________________________________________6.如果他们在派对观看录像,将会发生什么?______________________________________7.感到厌烦_______________=_________________8.什么时候是开派对的好时间?_________________________________做某事的时候____9.如果我们今天开,一半的学生不会再来__________________________________________10.让我们从餐馆订餐吧_______________________________11.如果我们要求人们带来食物,他们将只会带土豆条和巧克力________________________________________________要求某人做某事_____________ 12.他们将会太懒了而不能做饭__________________________=________________________=____________________________太…而不能____________13.如果他们赢了的话我们应该给人们一些小礼物___________________________________14.游戏将会更让人兴奋___________________________15.我不知道要做什么_________________________________16.如果我去派对的话,他们将会伤心_____________________________________17.告诉我们穿好看的衣服______________________________告诉某人做某事___________18.如果我穿牛仔裤,我将看起来最糟糕___________________________________________19.我不确定怎样去派对_________________________________20.如果我步行,将花费我太长时间______________________________________21.花费某人多长时间做某事______________________________22.如果我乘坐出租车,将会太贵了______________________________________23.你能给我一些建议吗?______________________________________24.一条建议____________________一些条建议______________一些建议____________25.得到足够的锻炼_____________________体育锻炼______名词,英语练习_______名词26.有足够的时间去学习________________________to do表___________27.环游世界___________________28.去大学____________________=_____________________29.赚很多钱_______________________30.获得教育________________________31.参加狮子团队__________________八年级上册英语Unit10 SectionB知识点1.从专家那儿寻求建议_____________________2.他们自己保守秘密___________________________3.他们学业有问题________________________4.一些人相信最糟糕的事情是什么都不做________________________________5.在生活中问题和烦恼是正常的________________________________________6.和别人聊聊帮助很多____________________________________知识点:________本句动名词:_________________谓语____________7.除非我们和其他人说说,否则我们将感到更糟糕_______________________________8.担心了数天_______________for表示______________9.她害怕把它告诉她父母_______________________________10.步行3英里去学校_______________________11.继续思考_______________________12.在最后_______________在…最后_____________13.他自己犯粗心的错误_____________________14.给她买了个新钱包___________________15.要求她更小心___________________________16.记得分享我的问题_________________________17.关于普通问题给与学生建议_______________________________18.他和她感觉一样_______________________19.最好不要逃避我们的问题________________________________20.尽力解决它们_________________________21.第一步是找个你信任的人来聊聊__________________________________22.没有必要成为一个专家_________________________________23.有更多的经验_________________________24.分享问题就像把它切成了一半________________________________知识点________25.通过跟别人聊聊这个问题,你就解决了问题的一半_____________________________做…就相当于完成了事情的一半_____________________通过做某事___________26.和你父母讨论你的问题__________________27.同意某人_________________不同意某人____________________28.有其他的两个问题_____________________________29.参观敬老院______________________30.带给老人一些花儿__________________________带给某人某物___________=______31.旅行到一个新国家____________________32.给你寄一封信______________________发给某人某物_____________=____________33.如果青少年在外面待得太晚,他们的父母将会担心他们_________________________34.我和我的父母吵架_____________________________35.决定做某事___________________________单元语法小专题(Grammar Focus)语法精讲if引导的条件状语从句条件状语从句通常由连词if引导,意为“如果;假如;倘若”,表示在某种条件下,很可能会发生某种事情或不发生某种事情。
1.if条件状语从句的位置在if 引导的条件状语从句中,if 条件句位置比较灵活,可放在主句前面也可放在主句后面。
若放在主句前,从句后面要用逗号和主句隔开。
如:If he doesn't feel tired,he will visit the museum.=He will visit the museum if he doesn't feel tired.如果他不感觉累,他就去参观博物馆。
2.if条件状语从句的时态搭配(1)当主句用一般将来时,if 引导的条件状语从句要用一般现在时。
如:If it rains tomorrow,I won't climb the hills.如果明天下雨,我就不爬山。
(2)当主句中含有can,may,must等情态动词时,if 引导的条件状语从句要用一般现在时。
如:We can win the basketball game if he joins us.如果他加入我们,我们就能赢这场篮球赛。
(3)当主句是祈使句时,if 引导的条件状语从句要用一般现在时。
如:Help your mom with the housework if youfinish your homework early.如果你完成作业早,就帮你妈妈做家务。
if条件状语从句用法歌诀:if 条件句不一般,几个要点记心间;条件句,放在前,逗号要放句中间;条件句,表可能,主句多用将来时;条件句,表事实,主句常用现在时。
3.与其他句式之间的转换(1)借助“祈使句+and/or+一般将来时的句子”这一句型来转换。
and在句意上表示顺承关系,or表示转折关系。
如:If you get up early,you'll get there on time.=Get up early,and you'll get there on time.=Get up early,or you won't get there on time.早点起床,你就会准时到那里。
(2)借助介词without或with来转换条件状语从句。
如:If there is no water,fish will die.=Fish will diewithout water.如果没有水,鱼就会死。
If you help me,I'll finish the work soon.=With your help,I'll finish the work soon.如果你帮助我,我就会快点完成工作。