when引导的时间状语从句可以接一段时间或者一个具体的时间点,从句的谓语动词可以是延续性的动词,也可以是瞬时动词。when表示“当…时”“在…时”,或"就在那时"。
【1】在过去,when从句和主句的动作先后发生
解释:表示在过去,主句和从句包含的动作先后发生了,或者主句或从句的动作先发生。
句子结构:when从句和主句都用过去式。
例句:
When I lived in the countryside, I used to carry some water for him.
当住在农村时,我常常为他担水。
When they began to talk about him he pricked his ears.
当他们开始议论到他时,他竖起了耳朵。
说明:
主句过去式常用 was(were) about to, was (were) on the point 等词组。如:
We were about to leave when he came in.
我们就要离开,就在那时他进来了。
We were about to start when it began to rain.
我们刚要出发就开始下雨了。
He was on the point of leaving when someone knocked at the door.
他刚要走就有人敲门。
【2】在过去,主句动作发生时,when从句动作正进行
解释:表示在过去,当主句的包含动作发生时,从句的动作在当时也正在进行。此类句子主句动词为瞬间性,从句动词为延续性。
句子结构:when从句用过去进行时,主句用过去式。
例句:
When rolling down the hill, he snatched at a rock.
在向山下滚的过程中,他一把抓住了一块岩石。
When running, he stumbled me.
跑动之中他把我绊倒了。
When I was having breakfast,my dad went out of home.
当我吃早饭的时候,我爸爸就出门了。
【3】在过去,when从句动作发生时,主句动作正进行
解释:表示在过去,当从句的动作发生时,主句的动作在当时也正在进行。此类句子主句动词为延续性,从句动词为瞬间性。
句子结构:when从句用过去式,主句用过去进行时。
例句:
When I got up,my mum was serving breakfast.
当我起床的时候,我妈妈正在给我准备早餐。
When she came in, I was eating.
她进来时,我在吃饭。
【4】在过去,when从句动作发生时,主句动作已完成
解释:表示在过去,当从句包含的动作发生时,主句的动作在从句动作发生之前已经完成了。
句子结构:when从句用过去式,主句用过去完成时。
例句:
When I got up,my mum had already (taken breakfast and) left.
当我起床的时候,我妈妈已经(吃了早饭)离开了。
The newsreel had almost finished when I went to the cinema.
我到电影院的时候新闻片几乎要演完了。
I had only danced with Mary about three minutes when someone cut in.
我和玛丽刚刚跳了大约三分钟的舞,就有人来截舞。