语法专项-if引导的条件状语从句（无答案）教案

语法专项-if引导的条件状语从句

【学习目标】

掌握if引导的条件状语从句的用法

【要点梳理】

条件状语从句

一．条件状语从句的概念

条件状语从句，表示主句动作发生的条件。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。 

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。

3.表示普遍真理和客观事实

例如：

If you heat ice, it melts

If you put oil on water, it floats.

If the temperature drops to 0 degrees Centigrade, water freezes.

由上述诸例可以看出，凡表示不受时间限制的自然法则的条件句，其if-分句和主句的位于动词都用一般现在时

4.表示现在习惯性动作

例如：

If I make a promise, I keep it.

If you go to the movies, what kind of movie do you prefer to see?

If it rains, I go to work by car.

在上述表示现在习惯动作的条件句中，if-分句和主句的位于动词也都是用一般现在时

5.表示过去习惯性动作

例如：If it rained, I went to work by car.

If I made a promise, I kept it.

If I was hungry, I usually had a full meal.

在上述表示过去习惯动作的条件句中，if-分句和主句的谓语动词都用一般过去时：

【当堂小测】

一．单项选择

1. Take the exam with great care, ______ you won’t get a good mark.

A. if     B. unless     C. or        D. and

2. Work harder ______ you will find it not difficult to learn.

A. if     B. unless     C. or        D. and

3._______ you put your heart into studies, you can’t get good grades in the exam.

A. If     B. Unless    C. When     D. Though

4. If  he ______ harder, he will catch up with us soon.

A. study  B. studies   C. will study   D. studied

5. —I wonder if Yao Ming ______ to our school this weekend.

—If  he _______, we will be very happy.

A. comes; comes  B. comes; will come  C. will come; comes   D. will come; will come

6. We didn’t start the party ______ everybody arrived.

A. since      B. if       C. until

7. ______ they are brothers, they don’t look the same.

A. Though     B. If       C. so       D. Who

8. If  it _______ tomorrow, I’ll stay at home.

A. will rain     B. rains     C. rained

9. I don’t know when he ______ tomorrow. If he ______, I’ll let you know.

A. comes; comes   B. comes; will come   C. will come; comes    D. will come; will come

10. —Would you mind ______ I ask you a question?

—Of course not, please do.

A. that    B. if      C. which      D. when

11. Do you know the saying “If you ______ life, life _____ you back.”?

A. love; love   B. love; will love   C. will love; love    D. will love; will love

12. Study hard, _____ you can pass the exam easily.

A. if     B. and     C. or        D. unless

13. If you work_________, you_________the exam.

A.hard;pass  B.hardly;will pass    C.hard;will pass  D.hard;won’t

14.Work hard, _______you will fail the exam.

A. and   B.or    C.but   D.because

15.If you _____ to the party, you’ll have a great time.

A. will go  B. went  C. go   D. going

16．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

17. – 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

二．完成句子

1. 如果努力学习，你就会取得好成绩。

If you__________, you __________ good marks.

2. 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.

3. 如果我们为他组织生日聚会，大家都会来的。

Everyone __________ if we __________ a birthday party for him.

4. 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 with you.

5. 如果他有空，他会帮助你的。

If he _____________, he _____________ you.