Question

英语语法：连接副词 whlie 和 when 当他们都表示时间段的时候 是否都必须用进行时?例如：：：

Answer 1

when当.的时候通常指点时间,从句的谓语动词用瞬间动词；也可以是一段时间,从句中的谓语动词用延续性动词.

eg:The boy was walking down the street when the UFO landed.

while 当.时候,只接一段时间,从句的谓语动词要用延续性动词.

eg:While he was eating ,I asked him to lend me some money.

while 连接的状语从句也可表示两个动作同时发生.

eg:While she was having lunch with her mother,I was playing in the park.

while还有然而的意思