初中英语――条件状语从句(精)

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 loo k 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。