Question

where when 在时间状语从句中的区别.

Answer 1

as,when 都可解释为“当…时候”,用来引导时间状语从句,但有区别：
1、when 意为 at the time that“在…时”,多指“时间点”,例如：
When he returned from work,his wife was cooking.
他下班回家时,他的妻子正在做饭.
2、as 意为 at the same time that“正当……”或“与……同时”,它兼指“时间点”和“时间段”,从句的动词既可是短暂性动词,也可是持续性动词.例如：
The door bell rang as we were having breakfast.
正当我们吃饭的时候,门铃响了.
As the time went on,the weather got worse and worse.
随着时间的推移,天气越来越糟.