when和while的用法解析、练习题及答案（附总结表格）
一、讲解三例句:
1. The girls are dancing while the boys are singing.
2. Lucy’s mother is cooking when she gets home.
3. When/While Lucy’s mother is cooking, she gets home.
二、用when或者while填空
1.______ Margo was talking on the phone, her sister walked in.
2.______ we visited the school, the children were playing games.
3.______ Sarah was at the barber’s, I was going to class.
4.______ I saw Carlos, he was wearing a green shirt.
5.______ Allen was cleaning his room, the phone rang.
6.______ Rita bought her new dog; it was wearing a little coat.
7. He was driving along ________ suddenly a woman appeared.
8. _____ Jake was waiting at the door, an old woman called to him.
9. ______ it began to rain, they were playing chess. 10. She saw a taxi coming ______ the woman was waiting under the streetlight.
三、语法
while和when都是表示同时，到底句子中是用when还是while主要看主句和
从句中所使用
的动词是短暂性动作(瞬时动词)还是持续性动作。
1、若主句表示一个短暂性动作，而从句表示的是一个持续性动作时，用
When/While。如:
He fell asleep when while he was reading. 他看书时睡着了。
I met him when while I was taking a walk in the park. 我在公园散步时遇到了他。
2、若主、从句表示的是两个同时(或几乎同时)发生的短暂性动作，一般要用when。如:
I thought of it just when you opened your mouth. 就在你要说的时候，我也想到了。
3、若主句是一个持续性动作，而从句是一个短暂性动作，用when 如:
When he came in, I was listening to the radio. 他进来时，我在听收音机。
It was raining hard when we arrived. 我们到达时正下着大雨。
4、若主、从句表示两个同时进行的持续性动作，且强调主句表示的动作延续到从句所指的
整个时间，通常要用 while。如:
Don’t talk while you’re eating. 吃饭时不要说话。
I kept silent while he was writing. 在他写的时候，我默不作声。
至于什么是短暂性动作，什么是持续性动作，其实有个很简单的规律。就是如果是进行时态，
一般是持续性的。如果是过去式，一般是短暂性动作。
四、表格总结
主句从句短暂性动作持续性动作 When/While 短暂性动作短暂性动作When 持续性动作短暂性动作 When 持续性动作持续性动作 while
五、习题答案(第2、10两道题目需要注意)
When/While 1
When 2
While 3
When 4
When/While 5 When 6
When 7
When/While 8 When 9
When/While 10
