谁知道as,when,while的用法的区别

谁知道as,when,while的用法的区别

七、while与when以及as之间的区别.1.当从句中的谓语动词是持续性的动作时,我们可以用while,when或as.While / When / As I was walking down the street,I noticed a police car in front of the bank.我顺着马路往前走时,发现银行门前停着一辆警车.2.当从句中的谓语动词表示瞬间动作时,不可用while.He was on the point of leaving when someone knocked at the door.他正要走,这时有人敲门.3.如果谈论两个长动作,最常用的是while.While John was sitting biting his nails,I was working out a plan to get us home.约翰坐在那里咬指甲时,我想出了一个回家的办法.不过,as是可以用来说明两种正在发展或变化的情况的,这时as引导一个持续性的动作,主句中的动作与之同时进行.As we talked on,he got more and more excited.我们继续往下谈的时候,他越来越兴奋.4.如果表示两个短动作或事件同时发生,最常用的是as或just as,也可用when.Just as he caught the ball,there was a tearing sound.当他抓住球的时候,有一种撕裂的声音.I thought of it just when you opened your mouth.就在你要说话的时候,我也想到了.======以下答案可供参考======供参考答案1:引导时间状语从句when是最常用词，没有限制。As 强调两个动作同步进行，即“一边……一边……”They sang as they walked他们边走边唱while 强调在一个动作延续的过程中发生另外一件事。所以，while后用延续性动词，并且常用进行时

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