八年级上英语--If引导的条件状语从句

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

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。

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。

1．if从句用一般现在时，主句用一般将来时

If he runs he’l l 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。

2．if从句用一般现在时，主句用may/might/can

If 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。

3．if从句用一般现在时，主句用must/should

If you want to lose weight you must/should eat less bread. 如果你想减肥，你必须少吃面包。

4．if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。

5．if从句用现在进行时，主句用一般将来时

If you are looking for Peter you’ll f ind him upstairs. 如果你是在找彼得，上楼就会找到他。

6．if从句用现在完成时，主句用一般将来时

If you have finished dinner I’ll ask the waiter for the bill. 如果你吃完了，我就叫服务生来算账

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

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 ___________________.