初中英语――条件状语从句（讲解&练习）
Ⅰ条件状语从句的定义 Ⅱ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, we'll 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 you're happy,i will be happy. 只要你高兴，我就高兴。 Ⅲ条件状语从句的种类 Ⅳ条件状语从句的时态原则 条件句 真实 从句 一般现在时 一般过去时 be动词用（were） 用 法 ① 主句为一般将来时态，if从句用一般 现在时态（即主将从现）。 ② 主句中含有情态动词，if从句用一般现在时态。 主句 一般将来时 情态动词+动原 祈使句 would/could+动原 例 句 非真实 We will stay at home if it rains tomorrow. 如果明天下雨，我将要呆在家。 If you finish your homework, you can go home now.如果你做完了作业，你现在可以回家了。 ③ 主句为祈使句，if从句用一般现在时态。 Don’t jump into the river if you feel very hot. 如果你感到很热，不要跳入河里。 ④ 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 wouldn’t 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 very happy. 如果你给我一些钱，我就会很高兴的。
二、if 引导的条件状语从句
（1）“if 从句+祈使句”的句子。其实，if 作为一个连词，主句也可以是其他形式的句子。 例如：If you want to go, please let me know.
(2)“祈使句 + and (or)+ 陈述句”
注意：A. “祈使句 + and + 陈述句”可以转化为 if 引导的肯定条件状语从句，而且主语是第二人称。
B. “祈使句 + or + 陈述句”可以转化为 if 引导的否定条件状语从句，而且主语是第二人称。
例如：1.Study hard and you will pass the exam.
=If you study hard, you will pass the exam.
2. Hurry up, or you’ll be late. =If you don’t hurry up, you’ll be late. 考题：Work hard，________ you may catch up with your classmates soon.
A.or B.but C.and D.yet
小试牛刀：用 if 连接下列句子
1、Go to bed early and you will have a good rest.
2、Hurry up, or you’ll miss the bus.
注意 ：
学习\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。
【边学边做】用括号内所给词的正确形式填空。
1. What will you buy if you ________（have）a lot of money? 2. If it ________（not snow）tomorrow, we will feel unhappy. 3. You mustn’t go to school if you ________（be）still in bed. 4. If he _______（be）at home at that time, he would know it. 5. Please show me the way if you ________（know）it.
6. You will hurt your teeth if you ________（eat）too much candy. 7. If you gave me a toy car, I _________（be）very happy. 8. I would get the prize if I _________（work）hard. 练习 Ⅰ.单项选择
（ ）1.If you _____ to the party, you’ll 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?
--We’ll go to the library tomorrow if it ___.
A. isn’t rain B. rain C. won’t rain D. doesn’t rain （ ）4. What will you do if you _____ to the old folk’s home?
A. go B. went C. going D. will go
（ ）5．I’ll give the book to him if he ___ here next Sunday.
A. will come B. comes C. is coming D. came
Ⅱ.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. Ⅲ.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 park _________ you. 24. 如果她睡过头了，就会旅游迟到的。
She;__________________________ the trip if she ___________________. 25. 如果他有空，他会帮助你的。
If he _________________, he _________________ you. 26. 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.