When和While的区别

When和While的区别

After school, I was about to enter my apartment while I saw a little dirty dog lying beside a dustbin.这道改错题应该把while改成when，但是很多学生都改不出来，这就是不明白when和while的区别，那么它们到底该怎么用呢？

while表示当……时候，相当于when 英语解释为during the time that sth is happening

eg.Her parents died while she was still at school.

她还在读书时，父母就去世了

while放在句中表示转折，对比，相当于but

eg.He likes swimming while I like reading

他喜欢游泳而我喜欢阅读

while放在句首翻译成虽然，尽管，相当于although

eg.While I am willing to help, I do not have much time available.

尽管我愿意帮忙，但我没多少时间。

at or during the time that 在……的时候，当……时

eg.I loved history when I was at school.

我上学时喜欢历史

while引导的从句只能用延续性动词，而when引导的从句可以用延续性动词也可以用非延续性动词。

when引导的从句动作和主句动作可以同时发生或在之后发生，while只能同时发生或存在