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 崇文英语 - 8年级 2006-4期 Lesson Zone GrammarExpress

掌握三要素巧学条件句


(江苏东台 卢爱龙)

if引导的条件状语从句是Unit 5的语法重点,也是各类考试命题的热点。如同学们掌握了其常见的三个要素后,可达到巧学妙记的“神效”。

No.1 基本要素

if意为“如果”,是连词,专门用来引导条件状语从句。由if引导的条件状语从句,既可位于主句之前,也可位于主句之后。当从句在前时,必须用一个逗号与主句隔开。试体会:

如果你不小心,车子会撞到你。
A car may hit you if you are not careful.
   主句          从句
If you are not careful, a car may hit you.
   从句          主句

No. 2 时态要素

在该句型中:①当主句是一般将来时,②当主句的谓语含有情态动词,③当主句的谓语含有want, wish, hope等动词,④当主句是祈使句时,与其连用的条件状语从句的谓语动词通常用一般现在时代替一般将来时。试体会:

如果他明天不能准时来,我们就不知道应该怎么办。
If he won't come on time tomorrow, we won't know what to do.
If he doesn't come on time tomorrow, we won't know what to do.

No.3 转换要素

对条件状语从句同义句转换的途径有:
① 借助“祈使句+and / or+句子(谓语通常用将来时态)”这一句型来转换。其中,and表示句意顺承;or表示转折,意为“否则”。试体会:

If you work hard, you'll pass the exam easily.
= Work hard, and you'll pass the exam easily.
= Work hard, or you won't pass the exam easily.

② 借助介词with或without来转化条件状语从句。试体会:

If there is no water, the fish may die.
= Fish may die without water.
If you help me, I'll finish my task soon.
= With your help / With the help of you, I'll finish my task soon.

③ 借助动词不定式短语来转化。试体会:

It will be a pity to leave him alone at home.
= It will be a pity if we leave him alone at home.

古人云“纸上得来终觉浅,绝知此事要躬行”。现在就让我们一起来感受一下与条件状语从句有关的经典中考试题。

A) 单项选择,选择最佳答案。
1. Frank     a film if he's free next Saturday. (2005 年北京)
 A. see   B. saw   C. has seen  D. will see
2. I am waiting for my classmate. If    , I will go running by myself. (2005 年江苏盐城)

 A. she doesn't come   B. she won't come
 C. she will come   D. she is coming

3. If he     harder, he will catch up with us soon. (2005年 湖南益阳)
 A. study   B. studies   C. studying  D. studied 
4. — What will Bill do if he     in the test?
 — He will try again. (2005年 北京崇文区)
 A. fail   B. fails   C. will fail  D. is failing
5. We won't go sightseeing if      tomorrow. (2005年 江苏杭州)
 A. it rains  B. it will rain   C. it would rain   D. it rained
B) 同义句转换,每空一词。
1. Run quickly, or you will be late for school. (2004年 江苏泰州)
     you            , you will be late for school.
2. Take enough money with you, and you can offer to buy the dictionary. (2005年 山西太原)
 You can offer to buy the dictionary                              .
3. It will be a pleasure for me to go there with you. (2003年 新疆课改区)
 It will be a pleasure for me     I     with you.
4. If there is no air, none of us can live. (2004年 宁夏)
 None of us can live        .
5. If you run fast enough, you will catch up with them. (2003年 湖北黄冈)
                ,      you will catch with them.


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