while在英语中一般有三种用法，分别如下：
一、 while 用作名词时,意为“一段时间,一会儿”：
I stayed there for a short while.
The postman came a short while ago.
1. 意为“当……时候,和……同时”,引导时间状语从句.例如：
While I was watching TV, the bell rang.
Meimei watched TV while she ate her supper.
2. 意为“虽然,尽管”,引导让步状语从句.例如：
While it was late, he went on working.
While he is in poor health, he works hard.
3. 连接两个并列句子,表示“对比”关系.例如：
He went out for a walk, while I stayed at home.
I like singing while she likes dancing.
You like sports, while I prefer music.
1. while 引导的时间状语从句既可放在句首,也可放在句末；而 while 引导的让步状语从句一般放在句首,不放在句末.另外,也可以从意义上加以区分.例如：
While he was tired, he went on working.
While he was tired, he would have a rest.
2. while 引导让步状语从句时,如果从句的主语和主句的主语相同,那么从句的主语和谓语动词 be 都可以省略.例如：
While he was ill, he went there. （= While ill, he went there.）
3. while 和 when 都可以引导时间状语从句,但应注意： while 引导的时间状语从句中的谓语动词必须是延续性的动词；而 when 引导的时间状语从句中的谓语动词既可以是延续性动词,也可以是非延续性动词.当时间状语从句中的谓语动词是延续性动词时, while 和 when 可以互相替换.例如：
While we were talking, the teacher came in.
The bus had left when we arrived at the bus stop.
（ arrive 是非延续性动词,因此,此句中的 when 不能用 while 替换.）
When / While we were having a meeting, our teacher came in.
（ have 是延续性动词,因此,句中的 when 可以用 while 替换.）
4. while 引导的状语从句还可以表示“某个动作正在进行的同时,另一个动作也在进行之中”.例如：
While the teacher was speaking, the students were listening.
While he was writing, I was reading
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