初中英语-条件状语从句

初中英语―条件状语从句

一．条件状语从句的概念

条件状语从句，即在某种条件下，一件事情可能发生。在英语中由连接词if或unless 等引导的状语从句叫做条件状语从句。条件是指某一件事情实现之后（状语从句中），一件事情（主句）才能发生，通常译作“假如，只要，如果”等意思。条件状语从句中，主从句的时态要遵循“主将从现”的原则。即，主句是将来时态时，从句用一般现在时代替将来时态。

二.条件状语从句的引导词

1.If conj . 如果，假如

If you ask him，he will help you．如果你请他帮忙，他会帮你的。

If you fail in the exam，you will let him down．

如果你考试不及格，你会让他失望的。

2.unless conj.除非,若不,除非在……的时候（if ...not...）

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。

Unless it rains, the game will be played.除非下雨,比赛将照常进行。

3.so/as long as conj.只要

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。

三．关于条件句的时态，常见的有以下三种情况：

1、条件状语从句的主句是一般将来时，那么从句常常用一般现在时。

When I grow up, I’ll be a nurse and look after patients.

我长大后要当一名护士，照顾病人。

2、如果主句是祈使句，那么从句通常要用一般现在时。

If you want to have a chat ,call me up.

如果你想聊天，打我电话。

3、如果主句是含有情态动词时，根据需要从句多用一般现在时。

You should be quiet when you are in the reading room.

在阅览室时应保持安静。

四．知识拓展

1在以when，before，as soon as等引导的时间状语从句，也适用“主将从现”原则，即如果主句是一般将来时，从句则用一般现在时。

I'll tell her the good news when she comes back.

当她回来的时候，我将把这个好消息告诉她。

she will give you a call as soon as she returns.

她一回来就会给你电话。

2.If条件句的同义句：祈使句，and /or+将来时态的陈述句。

Work hard ,and you will make great progress.=

If you work hard,you will make great progress.

如果你努力学习，你才会取得大的进步。

Hurry up, or you will be late.=If you don’t hurry up.you will be late.

如果你不快点，你就要迟到了。

条件状语从句的时态练习

一、用所给词的适当形式填空

1.When i ________(feel) tired, i _______________ (have) t a rest.

2. Where _______ he _________(see) the film if he ________________(have) time?

3.Unless there __________(be) many trees, there _______________( be) more pollution.

4. He _____________(dress) more casually unless he ________________ work) on

weekends.

5. If Marcia _____________(live) alone, she ___________________( keep) a pet parrot.

6. Lana ________________( buy) a new dress as soon as the old one __________(be) out of style.

7.The twins ______________(fight) when they_______________(argue).

8. I ____________(have) a bake sale if I _____________(need) money for education.

9. Peter _____________( send) me a beautiful souvenir as long as he _____________(tour) Spain.

10. As long as Mr Green __________(say) I am hard- working, my parents _________( feel) glad.

11.I ____________(go) to the beach if it________________ ( not rain) this week.

12. __________they __________( have) a match if the P.E. teacher _____________(be) busy?

13.He ____(write) a letter to his grandparentsas long as he ____(be ) free of task..

14. Unless she ____________(get) up late, she _____________ (catch) the early bus.

15. Peter ________(major) in English if he ____(pass) the exams in Peking University.

15.如果他到的晚了会发生什么事情？What _______________ if he _____________ late?

16. 如果努力学习，你就会取得好成绩。

If you__________ _________, you ___________ good _____________.

17. 他如果不看电视了，他的父母会很高兴。

Unless he _________ TV too much, his parents __________ __________ very happy.

18. 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. 19. 除非明天下雨，否则我将和你一起去公园的。

Unless it __________ __________ tomorrow, I ______________ go to the park _________ you.

20. 如果她睡过头了，就会旅游迟到的。

She;__________________________ the trip if she ___________________.