在英语学习中, when与 while都可以作连词引导时间状语从句。但是学生们时常混用它俩,认为其用法没什么区别。其实不然,下面就 when与 while的用法区别做一个较为详细的归纳。
一、根据从句动作的持续性来区分
1.“主短从长”型:即主句是一个短暂性的动作,而从句是一个持续性动作,此时两者都可用。如:
Jim hurt his arm while/ when he was playing tennis. 吉姆打网球时把手臂扭了。
When/ While she was waiting for the train, she became very impatient. 她在等火车时,变得很不耐烦。
2.“主长从长”型:即主句和从句为两个同时进行的动作或存在的状态,且强调主句动作或状态延续到从句所指的整个时间,此时通常要用 while。如:
I always listen to the radio while I'm driving. 我总是一边开车一边听收音机。
He didn't ask me in; he kept me standing at the door while he read the message. 他没有让我进去,他只顾看那张条子,让我站在门口等着。
3.“主长从短”型:即主句是一个持续性动作,而从句是一个短暂性动作,此时用 when,不能用 while。如:
It was raining hard when we arrived. 我们到达时正下着大雨。
When he came in, I was listening to the radio. 他进来时,我在听收音机。
二、根据主句与从句动作是否同时发生来区分
1.若主句与从句表示的是两个同时发生的短暂性动作,含有类似汉语“一……就”的意思,可用 when。如:
The ice cracked when I stepped onto it. 我一踩冰就裂了。
He jumped to his feet when the boss came in. 老板一进来他立刻站了起来。
Scarcely/ Hardly had we arrived, when it began to rain. 我们刚一到就下起雨来了。
2.若主句与从句表示的是两个几乎同时发生的短暂性动作,含有类似汉语“刚要……就”“正要……却”的意思,可用 when,且此时通常连用副词 just。如:
I caught him just when he was leaving the building. 他正要离开大楼的时候,我把他截住了。
Just when he two men were leaving, a message arrived. 就在这两个人要离开的时候,突然有了消息。
三、根据从句动作的规律性来区分
若暗示一种规律性,表示“每当……的时候”,英语一般要用 when。如:
It's cold when it snows. 下雪时天冷。
He smiles when you praise him. 你夸奖他时他总是笑笑。
四、根据主从句动作的先后顺序来区分
若主句与从句所表示的动作不是同时发生,而是有先后顺序时,一般要用 when。如:
When he arrives, he'll tell us all about the match. 等他到了,他会好好给我们讲讲那场比赛的情况。
When she had finished, she waited as though for a reply. 她讲完之后等了等,仿佛是在等候回答似的。
五、根据是否具有“趁机”意味来区分
若从句所表示的“当……的时候”具有“趁机”的意味,则通常用 while。如:
Strike while the iron is hot. 趁热打铁。
I tried to slip the note to him while the teacher wasn't looking. 我想趁老师不注意时把条子偷偷递给他。
有时也用 when。如:
He stole the money when no one was by. 他趁旁边无人时把钱偷走了。
The boy looks at her repeatedly when she's not looking. 那男孩趁她没看他的时候不断地盯着她看。
六、根据是否用作并列连词来区分
when可用作并列连词,表示“这时(突然)”; while也可以用作并列连词,表示“而”“却”(表示对比);但 as则没有类似用法。如:
I was just about to go to bed when I heard a knock on the door. 我正要睡觉,听见有人敲门。
One person may like to spend his vacation at the seashore, while another may prefer the mountains. 一个人会喜欢在海滨度假,而另一个人会喜欢在山里度假。
七、根据所引出的省略句来区分
1. when之后均可直接跟一个名词,构成省略句;但是 while一般不这样用。如:
When a boy, he lived in Japan. 他小时候在日本。
When still a student, he wrote a novel. 当他还是个学生的时候,他就写了一本小说。
2. when和 while之后可接现在分词、介词短语、形容词等构成省略句。如:
When/ While reading, he fell asleep. 他看书时睡着了。
When/ While in trouble, ask her for help. 遇到麻烦的时候你就去找她帮忙。
You must study hard while( you are) young, or you will regret when( you are) old. 少壮不努力,老大徒伤悲。