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.He was reading a book ______suddenly the telephone rang.
10. ______ it began to rain, they were playing chess.
11. She saw a taxi coming ______ the woman was waiting under the streetlight.
12. the allien was in the museum,I called the police.
13.The boy was walking down the street a UFO landed.
14. the alien was visiting the museum,the boy called the TV station.
15.I was cleaning my room the fire broke out.
16. Linda shouted his name,some people looked at her.
用所给动词适当形式填空
17.While Jake __________(look) for customers, he _______(see) a woman.
18. They ____________(play) football on the playground when it ______(begin) to rain.
19.A strange box ________(arrive) while we _________ (talk).
20. John ____________(sleep) when someone __________(steal) his car.
21.Father still (sleep)when I (get)up yesterday morning.
22.Grandma (cook) breakfast while I (wash) my face this morning.
23.Mother (sweep)the floor when I (leave)home.
24.I (read) a history book when someone (knock) at the door.
25.Mary and Alice are busy (do)their homework.
26.The teacher asked us (keep) the windows closed.
27.I followed it (see)where it was going.
28.The students (play)basketball on the playground from 3 to 4 yesterday afernoon..
完成下面句子，词数不限
1. 飞机在伦敦起飞时正在下雨。
It when the plane in London.
2. 你记得汶川大地震时你在做什么吗？
Do you what you when Wenchuan Earthquake .
3. 当铃声想起的时候，我们正在操场上玩得很开心。
We on the playground when the bell .
4. 当妈妈下班回家时，你在做什么？
Mum from work?
5. 当我在做作业时，有人敲门。
，someone the door.
6. 当外星人正在买纪念品的时候，那个女孩报了警。
答案 1.while 2.when 3.while 4.when 5.while 6.when 7.When 8.While 9.When 10.When 11.While 12.when 13.when 14.while 15.when 16.when 17.was looking ,saw 18.were playing,began 19.arrived, were talking 20.was sleeping, stole 21.was, sleep,got 22.was cooking,was washing 23.was sweeping,left 24,was reading,knock 25,doing 26.to keep 27. to see 28.were playing
1.was raining,took off
2. remember , were doing ,took place
3.were having fun, rang
4.what were you doing when ,came back home
5.while /when I was doing my homework ,knocked at
6.while the alien was buying the souvenirs,the girl called the police.
（一）、when，while都有“当……时候”的意思。
when既可表示某一点时间，也可以表示某一段时间。
在when引导的时间状语从句中，其谓语动词可以是延续性的，也可以是非延续性的，可与主句中的谓语动词同时发生，也可在其后发生。
1、I was just reading a book when she came into my room.
她走进我房间时，我正在看书。
2、Were you writing when the teacher came in?
老师进来的时候，你在写信吗？
3、When he was a child he was always trying out new ideas.
他小时候就常常试验一些新的设想。
（二）、while只能表示某一段时间，不能表示某一点时间。
在while引导的时间状语从句中，其谓语动词只能是延续性的，而且也只能与主句中的谓语动词同时发生或存在。
例如：
1、While Jim was mending his bike, Lin Tao came to see him.
正当吉姆修自行车时，林涛来看他。
2、You can’t do your homework while you’re watching TV.
你不能一边看电视一边做家庭作业。
（三）、另外，when和while的区别还在于：while引导的时间状语从句多用进行时态，而when引导的时间状语从句多用一般时态。
例如：
1、While they were talking , the bell rang.
正在他们谈话的时候，上课铃响了。
2、I was doing my homework when my mother came back home yesterday evening.
昨天晚上妈妈回家的时候，我正在做家庭作
注意：
1) 如主句谓语动词表示的是短暂动作，从句时间状语指一段时间，when while as 三者可通用。
Peter came in while /as I was watching TV.当Peter进来的时候我正在看电视。
I was watching TV when Peter came in. 当Peter进来时我正在看电视。
2) as 和when 可与非延续性动词连用，而while 只能与延续性动词连用。
例如：He came in when/ as I was going to bed.我正要上床睡觉，他进来了。
3) as 和while可用来指一段时间，但as 强调主句与从句表示的动作同时发生，while强调主句表示的动作是在while 从句的动作延续中发生。
As my mother sang those old songs, tears ran down her cheeks.
当我妈妈唱起那些老歌时，眼泪顺着她的脸颊流了下来。
I came in while he was reading an interesting book in his room.。
