新概念二IF从句.doc

一、条件状语从句 一） if引导的条件状语从句 （if意思为“如果”，主将从现）用 法 例 句 主句为一般将来时态，if从句用一般现在时态（即主将从现）。We will stay at home if it rains tomorrow. 主句中含有情态动词，if从句用一般现在时态。If you finish your homework, you can go home now. 主句为祈使句，if从句用一般现在时态。Dont jump into the river if you feel very hot. 主句为过去将来时，if从句用一般过去时态（如果涉及到be动词，一律都用were）。此时，表达的是和现实相反的推测，用虚拟语气。If I were you, I wouldnt do it like that.如果我是你，我就不会那么做的。If you gave me some money, I would be veryhappy.如果你给我一些钱，我就会很高兴的。A： if 条件句的时态搭配1if从句用一般现在时，主句用一般将来时 (如果表示可能发生的事)If he runs hell get there in time. If you go to bed earlier, you wont feel tired next morning.2if从句用一般现在时，主句用may/might/can/ must/shouldIf the fog gets thicker the plane may/might not take off. If it stops snowing we can go out. If you want to lose weight you must/should eat less bread. 3if从句用一般现在时，主句用一般现在时 (如果表示必然发生的事情)If you heat ice it turns to water. 如果把冰加热，它就会化成水。If bears are in danger ,they attack people.If you drop a glass, it breaks. B: if 引导的条件状语从句的用法总结 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。在if 引导的条件状语从句中，if 和条件句位置灵活，但不管怎样，一定要学会冷静分析句意和句子结构。特别提醒： If 只有当作为“如果”的意思时，才符合主将从现原则； 如果If 作为“是否”的意思时，则不符合主将从现原则。 二） unless 引导的条件状语从句，意思相当于 if.not. , 语气比较强。 （主将从现）Youll fail the exam unless you study hard.=Youll fail the exam if you dont study hard.三）so/as long as 引导的条件状语从句，表示 “只要” （主将从现）As long as I know the money is safe, I wont worry about it.As long as it doesnt rain, we can play football.二、时间状语从句以when，before，as soon as，once等引导的适用“主将从现”原则Ill tell my mother the good news when she comes back.she will call you as soon as she returns.Once you see the film, you will never forget it. 一旦你看了这部电影，你将永远不会忘记。三、 If条件句的同义句1. 借助“祈使句+and /or+简单句”，其中and 表示句意顺承，or表示转折。If you work hard, you will pass the exam.= Work hard ,and you will pass the exam. If you dont hurry up. you will be late.=Hurry up, or you will be late.2. 借助介词with或without来转换。 If you help me, Ill finish my job soon. =With your help, Ill finish my job soon. If you dont give me a hand, I ll not complete it in such a short time.= Without your help, I wont complete it in such a short time. 课堂训练：1) 勾选正确的答案完成句子。1.Daina ( will go/go/goes) to Europe if she (will pass/pass/passes) the exams .2. The graduates (will teach/teach/teaches) in the poor village if the Ministry of Education (will agree/ agree/agrees) soon.3. If there (will be/ are/is) a car accident, they (will call/call/calls) 110 for help at once.4. If it (wont/dont/doesnt/ isnt) rainy, we (will take/ take/takes) walk outside.5. If a UFO (will land/land/lands) in front of me, I (will go/go/goes) in to look for the alien.6. If he (will have/have/has) money, he (will build/build/builds) a science lab.7.Dont wait for me if I (am/ will be) late.8.They (wont/dont) go to the beach if it (will rain/rain /rains).9. I (will call/ call) you if he (will stay/stay /stays) at home.10. Mr Smith (will let/ let/lets) you know if he (will need/ need/ needs) help.11. (Will / Do/ Does) he visit the museum if he (wont / dont/ doesnt) get tired?12. Where (will/ do/does) they live if they (will miss/ miss/ misses) the bus?2) 用所给词的适当形式填空1.If you _(feel) tired, you _ (have) to have a rest.2. Where _ he _(see) the film if he _(have) time?3. If there _(be) fewer trees, there _( be) more pollution.4. He _(dress) more casually if he _( not work) on weekends.5. If Marcia _(live) alone, she _( keep) a pet parrot.6. Lana _( buy) a new dress if the old one _(be) out of style.7.The twins _(fight) if they_(argue).8. I _(have) a bake sale if I _(need) money for education.9. Peter _( send) me a beautiful souvenir if he _(tour) Spain.10. If Mr Green _(say) I am hard- working, my parents _( feel) glad.11.I _(go) to the beach if it_ ( not rain) this week.12. _they _( have) a match if the P.E. teacher _(be) busy?13.He _(write) a letter to his grandparents if he _(get) his report card this week.14. If she _(get) up late, she _ ( not catch) the early bus.15. Peter _(major) in English if he _(pass) the exams in Peking University.16. What will you buy if you _（have）a lot of money?17. If it _（not snow）tomorrow, we will feel unhappy.18. You mustnt go to school if you _（be）still in bed.19. If he _（be）at home at that time, he would know it.20. Please show me the way if you _（know）it.21. You will hurt your teeth if you _（eat）too much candy.22. If you gave me a toy car, I _（be）very happy.23. I would get the prize if I _（work）hard.24. I dont know if you (come) tomorrow.25. I dont know if you (like) this present.3) 按照中文意思完成英文句子1.如果他到的晚了会发生什么事情？What _ if he _ late?2. 如果努力学习，你就会取得好成绩。If you_ _, you _ good _.3. 他如果看电视太久了，他的父母会不高兴。If he _ TV too much, his parents _ _ unhappy.4. 如果我们为他组织生日聚会，大家都会来的。Everyone _ if we _ a birthday party _ him.5. 如果明天不下雨，我会和你一起去公园的。 If it _ _ tomorrow, I _ go to the park _ you.6. 如果她睡过头了，就会旅游迟到的。She;_ the trip if she _.7. 如果他有空，他会帮助你的。If he _, he _ you.8. 如果Tom考试不及格，他就没有机会上高中了。Tom _have the _to go to the _high school if he _ the exams.9. 你如果抄同学的作业就不能学好各门功课。You _ _ good at all the subjects if you _ the other students homework. 4) 单项选择（ ）1.If you _ to the party, youll have a great time. A. will go B. went C. go D. going（ ）2. It will be a long time _ Peter _ his work. A. since, has finished B. after, finishes C. when, will finish D. before, finishes.（ ）3. What will father _ us from Japan? A. take B. bring C. carry D. make （ ）4. Weifang is famous _ kites. A. for B. to C. on D. with（ ）5 I _ her the answer if she _me. A. can tell, will ask B. will tell, will ask C. would tell, ask D. will tell, asks（ ）6. What are you going to do tomorrow?-Well go to the library tomorrow if it _. A. isnt rain B. rain C. wont rain D. doesnt rain（ ）7.Do you know when he will come back tomorrow?-Sorry, I dont know. When he _ back, Ill tell you. A. comes B. will come C. come D. may come （ ）8. What will you do if you _ to the old folks home visit?A. go B. went C.going D. will go（ ）9. If I eat _ food, Ill be very fat.A. too many B. many too C. too much D. much too（ ）10. Ill give the book to him if he _ here next Sunday.A. will come B. comes C. is coming D. came（ ）11. There _an English film in our school tomorrow.A. is going to have B. will have C. is going to be D. has（ ）12. Could you tell us where _？A. will the next Olympic Games held B. the next Olympic Games will be heldC. would the next Olympic Games be held D. the next Olympic Games would be held（ ）13. When my mother returned last night, I _ a book. A. read B. am reading C. was reading D. am going to read（ ）14.What _ you _ when it began to rain?A. do, do B. were, doing C. are, doing D. did, do（ ）15. Ill wake you up when he _back.A. will B. is going to come C. comes D. come（ ）16. As soon as he _back, I_him a lesson.A. comeswill teach B. will comewill teachC. comesteach D. will cometeach5) 同义句转换1. You keep your brain active. You think faster. (用if将两句合成一句) .2.Youll forget the address. You write it down. (用unless将两句合成一句) .3.If you play basketball here，you may break the windows.（改为含if条件从句的复合句）_ _play basketball here, _you may break the windows.4. Get enough sleep , and we wont feel tired.（改为含if条件从句的复合句） _, we wont feel tired. 5. Think hard , or you wont find a better way. （改为含if条件从句的复合句） _, you wont find a better way. 6. You are going to copy others papers . The teacher wont let you take the exam. （改为含if条件从句的复合句）_, the teacher wont let you take the exam. 7. Lets go out for a walk unless you are too tired.（同义句） you are too tied, lets go out for a walk.1）选择题( ) 1. If he hard, he will get good grades. A. study B. studies C. will study D. studied ( ) 2. I want to know if Mary to the pa