1、2015-12-20条件状语从句1、定义由引导词if或unless引导的状语从句叫做条件状语从句。在英文中，条件是指某一件事情实现之后(状语从句中的动作)，其它事情(主句中的动作)才能发生，通常译作假如。(注意:在含有条件状语从句的复合句中，表示将来时态，主句是一般将来时态,祈使句或谓语动词是情态动词，从句要用现在时态,即主将从现原则。Eg1: Take the medicine, you will be fine.Eg2: If you can read as many English books as possible, your English will be improved.2、用法
2、语法引导条件状语从句最常用的连词是if, 由if引导的条件状语从句表示在某种条件下某事很可能发生if引导的条件状语从句既可以将从句放前面也可以将从句放后面。除了if之外，还有其他连词也可以引导条件状语从句。【注：在条件状语从句中，绝大数情况下some要变为any。】(1) unless conj.除非，若不，除非在的时候Eg1: You will fail to arrive there in time unless you start earlier.如果你不早点动身，你就不能及时赶到那儿。Eg2: Unless it rains, the game will be played.除非下雨，
3、比赛将照常进行。(2) on condition(that).在条件下，如果 on condition (that).引导的条件从句是主句事件发生的前提条件或唯一条件。Eg1: I can tell you the truth on condition that you promise to keep a secret.我可以告诉你真相，条件是你答应保密。Eg2: You can go swimming on condition (that) you dont go too far from the river bank.你只有在不远离河岸的条件下才可以下水游泳。 Attention（注意）：
4、 unless = if.not. Eg: Lets go out for a walk unless you are too tired.If you are not too tired, lets go out for a walk. if 引导的条件句有真实条件句和非真实条件句两种：真实条件句 Eg：If it rains tomorrow, we wont go on a park非真实条件句是虚拟语气的一种，表示与事实相反，主句用would do，从句用过去式，具有假设性，一定不会是真的,即所假设的事情基本不会有发生的可能。Eg：If I were you, I would go w
5、ith him.so/as long as （只要） 、in case（万一）引导。Eg1: So long as youre happy, it doesnt matter what you do. 只要你高兴，你做什么都没有关系。 You may borrow my book as long as you keep it clean只要你保持书的清洁，你就可以把我的书借去。Eg2: Take your umbrella in case it rains. 带着你的伞吧，以防下雨。“祈使句+and / or+简单句”。其中and表示句意顺承；or则表示转折，意为“否则”。Eg1: If yo
6、u work harder, youll pass the exam. = Work harder, and youll pass the exam. 如果你再努力些，你就会通过考试。 Eg2: If you dont hurry up, youll miss the train. = Hurry up, or youll miss the train. 如果你不快点儿，你就赶不上火车了。 3、练习题 .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 w
7、ill 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 4I _ her the answer if she _me. A. can tell, will ask B. will tell, will ask C. would tell, ask D. will te
8、ll, asks 5. 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 6.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 7. What will you do if
9、you _ to the old folks home visit? A. go B. went C. going D. will go 8. If I eat _ food, Ill be very fat. A. too many B. many too C. too much D. much too 9. Ill give the book to him if he _ here next Sunday. A. will come B. comes C. is coming D. came 10. There _an English film in our school tomorrow
10、. A. is going to have B. will have C. is going to be D. has 11. Could you tell us where _？ A. will the next Olympic Games held B. the next Olympic Games will be held C. would the next Olympic Games be held D. the next Olympic Games would be held 12. When my mother returned last night, I _ a book. A.
11、 read B. am reading C. was reading D. am going to read 13. What _ you _ when it began to rain? A. do, do B. were, doing C. are, doing D. did, do14. Ill wake you up when he _back. A. will B. is going to come C. comes D. come II. 同义句转换 1. Run fast, or youll be late for school. _ you _ _ fast, youll be
12、 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 _ _.、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 i
13、f 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(过时).7. The twins _(fight)（打架） if they_(argue).
14、8. Peter _( send) me a beautiful souvenir （纪念品）if he _(tour) Spain.9. If Mr Green _ (say) I am hard- working, my parents _( feel) glad.10.I _(go) to the beach if it_( not rain) this week.11. _they _( have) a match if the P.E. teacher _(be) busy?12.He _(write) a letter to his grandparents if he _(get
15、) his report card this week.13. If she _(get) up late, she _( not catch) the early bus.完成句子1.如果他到得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 _ hi
16、m.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 _ theother students homework.
