Question

when 和while引导的时间状语从句有什么区别？具体用法？非常感谢

Answer 1

when，while，as显然都可以引导时间状语从句，但用法区别非常大。
一、when可以和延续性动词连用，也可以和短暂性动词连用；而while和as只能和延续性动词连用。
① Why do you want a new job when youve got such a good one already？（get为短暂性动词）你已经找到如此好的工作，为何还想再找新的？
②Sorry，I was out when you called me．（call为短暂性动词）对不起，你打电话时我刚好外出了。
③Strike while the iron is hot．（is为延续性动词，表示一种持续的状态）趁热打铁。
④ The students took notes as they listened．（listen为延续性动词）学生们边听课边做笔记。
二、when从句的谓语动词可以在主句谓语动作之前、之后或同时发生；while和as从句的谓语动作必须是和主句谓语动作同时发生。
1．从句动作在主句动作前发生，只用 when。
①When he had finished his homework，he took a short rest．（finished先发生）当他完成作业后，他休息了一会儿。
②When I got to the airport，the guests had left．（got to后发生）当我赶到飞机场时，客人们已经离开了。
2．从句动作和主句动作同时发生，且从句动作为延续性动词时，when，while，as都可使用。
①When ／While ／As we were dancing，a stranger came in．（dance为延续性动词）当我们跳舞时，一位陌生人走了进来。
②When ／While ／As she was making a phonecall，I was writing a letter．（make为延续性动词）当她在打电话时，我正在写信。
3．当主句、从句动作同时进行，从句动作的时间概念淡化，而主要表示主句动作发生的背景或条件时，只能用 as。这时，as常表示“随着……”；“一边……，一边……”之意。
① As the time went on，the weather got worse．（as表示“随着……”之意）
② The atmosphere gets thinner and thinner as the height increases．随着高度的增加，大气越来越稀薄。
③As years go by，China is getting stronger and richer．随着时间一年一年过去，中国变得越来越富强了。
④The little girls sang as they went．小姑娘们一边走，一边唱。
⑤The sad mother sat on the roadside，shouting as she was crying．伤心的妈妈坐在路边，边哭边叫。
4．在将来时从句中，常用when，且从句须用一般时代替将来时。
①You shall borrow the book when I have finished reading it．在我读完这本书后，你可以借阅。
②When the manager comes here for a visit next week，Ill talk with him about this．下周，经理来这参观时，我会和他谈谈此事。
三、when用于表示“一……就……”的句型中（指过去的事情）。
sb．had hardly（＝scarcely） done sth．when．．．＝Hardly ／ Scarcely had sb．done sth．when．．．
①I had hardly ／scarcely closed my eyes when someone knocked at the door．＝Hardly ／ Scarcely had I closed my eyes when someone knocked at the door．我刚一闭上眼，就有人在敲门了。
②I had hardly ／scarcely entered my room when the telephone rang．＝Hardly ／Scarcely had I entered my room when the telephone rang．我刚一走进房门，电话就响了。赞同61| 评论(4)

Answer 2

(1) when当（在）……时候，既可表示某一点时间，也可以表示某一段时间，引导的从句谓语多用终止性（瞬间）动词，主从句的动作可同时也可以有先后顺序发生。
I was just reading a book when she came into my room. 她走进我房间时，我正在看书。
Were you writing when the teacher came in? 老师进来的时候，你在写信吗？
When he was a child he was always trying out new ideas. 他小时候就常常试验一些新的设想。
(2) while正当（正在）……时（指同时），只能表示某一段时间，不能表示某一点时间。
在while引导的时间状语从句中，其谓语动词只能是延续性的，而且也只能与主句中的谓语动词同时发生或存在。
While Jim was mending his bike, Lin Tao came to see him. 正当吉姆修自行车时，林涛来看他。
You can’t do your homework while you’re watching TV. 你不能一边看电视一边做家庭作业。
Some students were reading while others were writing. 有些学生在读书，而有些学生在写字。
(3) while引导的时间状语从句多用进行时态
而when引导的时间状语从句多用一般时态。
While they were talking , the bell rang. 正在他们谈话的时候，上课铃响了。
I was doing my homework when my mother came back home yesterday evening.
昨天晚上妈妈回家的时候，我正在做家庭作业。

Answer 3

when与连续性的或短暂性的动词连用，从句的动作与主句的动作有可能是同时发生，也可能是从句的动作发生在前，在表示两个动作同时发生时，可与WHILE互换。例如；when we were leaving，it began to rain，when引导的从句动词是leave，发生在rain之前。
While译为“在……同时”，“在…期间”，谓语动词要加延续性动词。例句：please be quiet while i ’m talking to you,。(个人经验,从句中是进行时时态时,一般都用while)
注;when 和while都可做并列连词,此时when表示”就在此时”,while可以译为然而,但是,表转折,强调.例句:he is good at basketball,while his brother is dood at football.