八年级上英语 If引导的条件状语从句.doc

13夏 八年级英语 语法专项 if引导的条件状语从句专项练习I条件状语从句的定义：引导条件状语从句最常用的连词是if，常见的if条件状语从句表示在某条件下，某事很可能发生，条件是可能存在的，主句中某种情况发生的概率也是很高的。If you ask him，he will help you如果你请他帮忙，他会帮你的。 If you have finished the homework， you can go home如果你作业做完了就可以回家了。另外，if从句还表示不可实现的条件或根本不可能存在的条件，也就是一种虚拟的条件或假设。从句多用一般过去时或过去完成时，表示对现在或过去的一种假设。如： If I were you，I would invite him to the party如果我是你，我会邀请他参加聚会。 I would have arrived much earlier if I had not been caught in the traffic要不是交通堵塞，我本会来得早一些。条件状语从句的引导词 1.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 we pay much attention to the earth, well have a better world.如果我们多关爱地球，就会拥有一个更美好的世界If it rains tomorrow, what shall we do?如果明天下雨，我们怎么办？注意：if还可以引导虚拟条件句，表示不可实现的条件，从句中多用一般过去时或过去完成时。What would happen if there were no water ?如果没有水会怎样？2.unless引导的条件状语从句：unless的意思是如果不，除非。可与if.not互换。You will fail in English unless you work hard.你英语考试会不及格的，除非你更加努力。3.as /so long as引导的条件状语从句：as /so long as意思是“只要”So long as youre happy,i will be happy.只要你高兴，我就高兴。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 If he runs hell get there in time. 如果他用跑的，他就会及时赶到那儿。The cat will scratch you if you pull her tail. 如果你拉猫的尾巴，它就会抓你。2if从句用一般现在时，主句用may/might/canIf the fog gets thicker the plane may/might be diverted. 如果雾在大一些，飞机可能就会改在别的机场降落。If it stops snowing we can go out. 如果雪停了，我们就可以出去。3if从句用一般现在时，主句用must/shouldIf you want to lose weight you must/should eat less bread. 如果你想减肥，你必须少吃面包。4if从句用一般现在时，主句用一般现在时If you heat ice it turns to water. (也可用will turn)如果把冰加热，它就会化成水。5if从句用现在进行时，主句用一般将来时If you are looking for Peter youll find him upstairs. 如果你是在找彼得，上楼就会找到他。6if从句用现在完成时，主句用一般将来时If you have finished dinner Ill ask the waiter for the bill. 如果你吃完了，我就叫服务生来算账条件状语从句的时态原则条件句从句主句真实一般现在时一般将来时情态动词+动原祈使句非真实一般过去时be动词用（were）would/could+动原V. 注意 ：学习 if 引导的条件状语从句的用法,现在总结一下: 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。 条件句表真实，主将从现要遵从； 条件句非真实，虚拟语气用到位。备注：在 if 引导的条件状语从句中，if 和条件句位置灵活，可直接放在主句后面，若 if 条件句放句首， 从句后面要加逗号，和主句隔开。还要注意前后时态一致原则。if引导的条件状语从句专项练习.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. 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（ ）3. 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（ ）4. What will you do if you _ to the old folks home?A. go B. went C. going D. will go（ ）5Ill give the book to him if he _ here next Sunday.A. will come B. comes C. is coming D. came.用所给词的适当形式填空6.If you _(feel) tired, you _ (have) to have a rest.7. Where _ he _(see) the film if he _(have) time?8. If there _(be) fewer trees, there _( be) more pollution.9. If Marcia _(live) alone, she _( keep) a pet parrot.11. Lana _( buy) a new dress if the old one _(be) out of style.12.The twins _(fight) if they_(argue).13. I _(have) a bake sale if I _(need) money for education.14. Peter _( send) me a beautiful souvenir if he _(tour) Spain.15. I _(go) to the beach if it_ ( not rain) this week.17. _they _( have) a match if the P.E. teacher _(be) busy?18. If she _(get) up late, she _ ( not catch) the early bus.翻译下列句子19.如果他到的晚了会发生什么事情？What _ if he _ late?20. 如果努力学习，你就会取得好成绩。If you_ _, you good marks.21. 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.22. 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.23. 如果明天不下雨，我会和你一起去公园的。 If it _ _ tomorrow, I _ go to the p