if的用法.ppt
一、时态一、时态 如果主句是一般将来时态，这时从句不可以用将来时态，而要用一般现在时。如果主句是一般将来时态，这时从句不可以用将来时态，而要用一般现在时。例如：例如： I wont go there with you if it rains tomorrow. 如果明天下雨的话，我就不和你一起去那儿了。如果明天下雨的话，我就不和你一起去那儿了。 二、主从句的位置二、主从句的位置 大多数情况下，从句可以位于主句之前，也可以位于主句之后。不过从句在大多数情况下，从句可以位于主句之前，也可以位于主句之后。不过从句在前时，主从句之间必须用逗号隔开。例如：前时，主从句之间必须用逗号隔开。例如： Please tell me if he comes back. = If he comes back, please tell me. 如果他回来了，请告诉我一声。如果他回来了，请告诉我一声。 三、三、if的两面性的两面性 if引导条件状语从句时意为引导条件状语从句时意为“如果如果”，如果引导宾语从句则意为，如果引导宾语从句则意为“是否是否”。请比较：请比较： 1) We will go out if it is fine tomorrow. 2) I dont know if the train has arrived. 句句1) 中中if引导的是状语从句。这个从句表示引导的是状语从句。这个从句表示“条件条件”，整个句子的意思是，整个句子的意思是“如果明天天气好，我们就出去如果明天天气好，我们就出去”。句。句2) 中中if引导的是宾语从句，充当谓语动词引导的是宾语从句，充当谓语动词dont know的宾语，整个句子的意思是的宾语，整个句子的意思是“我不知道火车是否到了我不知道火车是否到了”。1.If it _ sunny tomorrow, I _ boating. A. is go B. will be, go C. is, will go D. will be, will go2.-What will you do if it _ tomorrow, -Ill stay at home and watch TV. A. rain B. rains C. will rain D. is raining 1. Run fast, or youll be late for school. _ you _ _ fast, youll be late for school.2. You can buy the dictionary if you take enough money with you. Take enough money with you, _ _ _ buy the dictionary.3. If there is no air, none of us can live. None of us can live _ _. Ifdont runand you can without air if 条件状语从句的时态练习条件状语从句的时态练习 1. Diana (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 teacher (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.will gopasseswill teachagreeswill go lands will takeisnt will callis6. 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?rainsmisseswill doesntWill needswill letstayswill callwontamwill buildhas1.If you _ to the party, youll have a great time. A. will go B. went C. go D. going2. 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. with5.I _ her the answer if she _me. A.can tell, will ask B. will tell, will ask C. would tell, ask D. will tell, asks6. 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 rain7.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 go9. If I eat _ food, Ill be very fat.A. too many B. many too C. too much D. much too10. Ill give the book to him if he _ here next Sunday.A. will come B. comes C. is coming D. came11. There _an English film in our school tomorrow.A. is going to have B. will have C. is going to be D. has12. 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 held13. When my mother returned last night, I _ a book. A.read B. am reading C. was reading D. am going to read14.What _ you _ when it began to rain?A. do, do B. were, doing C. are, doing D. did, do15. Ill wake you up when he _back.A. will B. is going to come C. comes D. come1. 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.feelcan havecanseehasarewill bewill dressdoesnt worklivesshould/will keepcan/will buyis
