考點聚焦
1、時間狀語從句
(1)as、when、while用法一覽表。
as: as表示“當……的時候”,往往和when/ while通用,但它著重強調(diào)主句與從句的動作或事情同時或幾乎同時發(fā)生。
She came up as I was cooking. (同時)
The runners started as the gun went off.(幾乎同時)
when: (at or during the time that )既可以表示在某一點的時候,又可表示在某一段時間內(nèi),主句與從句的動作或事情可以同時發(fā)生也可以先后發(fā)生。
It was raining when we arrived. (指時間點)
When we were at school, we went to the library every day.(在一段時間內(nèi))
while: while意思是“當……的時候”或“在某一段時間里”。主句中的動作或事情在從句中的動作或事情的進展過程中發(fā)生,從句中的動詞一般要用延續(xù)性動詞。在when表示a period of time時,兩者可以互換。