Unit 10 If you go to the party, you'll have a great time

单元语法小专题（Grammar Focus）

语法精讲

if引导的条件状语从句的用法

　　条件状语从句通常由连词if引导，意为"如果、假如"，表示在某种条件下，很可能会发生某种事情。

　　1.if条件状语从句的位置

　　在 if 引导的条件状语从句中，if 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。如：

　　If I have time tomorrow, I'll go to the countryside with my friends.= I'll go to the countryside with my friends if I have time.如果我明天有时间，我将和我的朋友们去乡下。

　　2.if条件状语从句的时态搭配

　　if 引导条件状语从句，主句用一般将来时，从句则用一般现在时。如：

　　If it rains tomorrow, I won't climb the hills.如果明天下雨，我就不爬山。

　　温馨提示：在if 引导的条件状语从句中，有时根据句意的需要主句可能用到情态动词。如：

　　If you finish your homework, you can watch TV.如果你完成了家庭作业，你可以看电视。

　　3.if引导的条件状语从句与if引导的宾语从句的区别

　　 if 引导的条件状语从句，if意为"如果"，主句用一般将来时，从句则用一般现在时；if引导宾语从句时，if意为"是否"， 相当于 whether，时态需根据语境确定。如：

　　I don't know if it will rain tomorrow.我不知道明天是否会下雨。

　　if条件状语从句用法歌诀：

　　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，表可能，主句多用将来时；

　　条件句，表事实，主句常用现在时。

　　4.与其他句式之间的句型转换

　　(1)借助"祈使句+and (or)+一般将来时的句子"这一句型来转换。and在句意上表示顺承关系，or表示转折关系。如：

　　If you get up early,you'll get there on time.

= Get up early,and you'll get there on time.

=Get up early,or you won't get there on time.早点起床，你就会准时到那里。

　　(2)借助介词without或with来转换条件状语从句。如：

　　If there is no water, fish will die.=Fish will die without water.如果没有水，鱼就会死。

If you help me, I'll finish the work soon.= With your help, I'll finish the work soon.如果你帮助我，我就会快点完成工作。

语法精练

Ⅰ.用括号内所给单词的适当形式填空。

1.I_______ (buy) you a computer if you get good grades.

2.We_______ (not go) there if he doesn't agree.

3.You will win the match if you ________(practice) hard.

4.Please call me if you______ (have) any questions.

5.You may go swimming if you______ (finish) your homework.

Ⅱ.单项选择。

( )6.-Do you know when he will come back tomorrow?

-Sorry,I don't know.When he ________ back,I'll tell you.

( )7.Mary will go to Sanya if she _______ a five-day trip.

A.have B.had C.will have D.has

( )8.What will you do if you to the party without invitation?

A.go B.went C.going D.will go

( )9.If I eat too much food, I ______ too fat.

A.am B.was C.will D.will be

( )10.I'll give the book to him if he ______ here next Sunday.

C.is coming D.came

Ⅲ.改为同义句，每空一词。

11.Study hard, or you won't pass the exam.

If you study hard, you _____ ______ the exam.

12.Take a taxi,and you'll catch the train.

______ you ______ a taxi, you'll catch the train.

13.If you don't help me, I can't catch up with the others.

I can't catch up with the others______ _______ _______ .

14.Use your head and you'll have a good idea.

_____ you _____ your head,______ have a good idea.

15.If you are late,the teacher will be angry.

______ ______ late, ______ the teacher will be angry.