英语人教版八年级下册when 和while 的用法

when和while

when和while都可表示“当……的时候”，引导时间状语从句。你知道两者在过去进行时中的用法有什么不同吗？

请仔细观察下面的例句，然后补全空格中的内容。

①I was walking to school when I saw a cat in a tree.

②When Sally arrived home, her mother was cleaning the house.

主句的动作是持续性的，而从句动作是短暂性的，此时用_______引导时间状语从句，主句用_____________时态，从句用一般过去时态。

③While I was sleeping in the bedroom, someone knocked at the door.

④David fell while he was riding his bike.

主句的动作是短暂性的，从句的动作是持续性的，此时用_________引导从句，主句用____________时态，从句用过去进行时态。

⑤While Andy was waiting for the bus, he was reading a newspaper.

⑥He was cleaning his car while I was cooking.

主句和从句的动作在过去的某时刻或某段时间同时发生，而且动作都是持续性的，此时用_________引导从句，而且主句和从句都用_____________

时态。

练习：用when 和while 填空

1. We were singing __________ the teacher came in.

2. _________ I was doing my homework , my mother was cooking.

3. What were you doing _________ the rainstorm came ?

4. ________ I was waiting for the bus at the bus station, it began to rain.

5. ________ he woke up, the smoke was rising.