时间状语从句常用引导词：when, while, as, as soon as, before, after, till/until, since1、when, while, as（1）三者均可表示“当……时候”，如果主句表示的是短暂的动作，而从句表示的是一段时间，三者可通用。
如：I met Kang Li while/when/as I was walking along the street．当我沿街散步时碰见了康丽。
Don’t make any noise while/when/as I am recording. 我录音时（你们）别发出声音。
（2）while1）while只能与持续性动词连用，且常用进行时态。
表示主句的行为在从句行为进行的过程中发生。
如：While they were crossing the Atlantic, many people died. 他们中的很多人在横渡大西洋时丧生了。
2）表示主句和从句的动作同时发生。
如：While the wife was cooking, the husband was watching TV. 妻子在做饭的时候，丈夫在看电视。
3）表示“然而”，主句和从句是两个对应的动作。
如：Lucy likes dancing while Lily likes doing sports. 露西喜欢跳舞而莉莉喜欢运动。
（3）when1）when既可以和持续性动作连用，也可以和瞬间性动作连用，主句与从句描述的动作既可以同时发生，也可以先后发生。
如：When the weather is fine, many people go out for a walk. 天气好时，很多人都出去散步。
When I got home, I found my baby girl singing in the sitting room. 我到家时，发现我的小女儿正在客厅里唱歌。
2）表示“某人正在做某事，突然……”，主句用过去进行时，从句用一般过去时，表示一个动作正在进行的时候，另一个动作（突然）发生了，强调后一动作发生的突然性。
如：We were talking when the teacher came in. 我们正在讲话，老师（突然）进来了。
试比较：While we were talking, the teacher came in. 我们正在讲话的时候，老师进来了。
（不强调突然性。
）3）表示“某人正要做某事，就在这时……”，主句用过去将来时，从句用一般过去时。
如：I was leaving when somebody touched my shoulder. 我正要离开，就在此时有人碰了一下我的肩膀。
（4）asas与when用法相似，但着重强调主句动作与从句动作同时发生，有“随着……”或“一边……一边……”之意。
如：As you get older, you get more knowledge. 随着年龄的增长，你获得的知识就越多。
They sing as they walk. 他们一边走一边唱。
练习（一）用when, while, as填空1. I was looking out of the window ________ the teacher asked me.2. What is he doing ________ his parents came back?3. Mike was playing games ________ Jack was studying.4. I was about to fall asleep ________ the baby began to cry.5. ________ the children walked along the lake, they sang happily．6. Someone stepped on my toes ________ I was waiting for the bus.7. ________ she grew older, she became more responsible.（二）单项选择1. When I got to the factory, the workers _____ about the film.A. are talkingB. talkedC. were talkingD. have talked2. I _____ a letter when my mother came in.A. writeB. am writingC. was writingD. have written3. My mother _____ while my father _____ TV.A. cooks; was watchingB. was cooking; was watching;C. was cooked; watchedD. cooked; watched4. They were sleeping _____ they heard a man _____ “help”.A. when; shoutingB. while; to shoutC. when; to shoutD. while; shouting2、as soon as表示“一……就……”，强调动作紧密相连。
如：We began to work as soon as we got there. 我们一到那儿就开始工作了。
We always go somewhere interesting as soon as the holiday begins. 假期一开始，我们就会去某个好玩的地方。
I will write to you as soon as I arrive there. 我一到那里就会给你写信。
（主将从现）3、before, afterbefore表示“在……之前”，after表示“在……之后”。
如：Before we begin dinner, my father gives thanks for the food. 吃饭前，我父亲会表达感激之情。
Mother sometimes prepares dinner after I come back from school. 妈妈有时在我放学回家后才准备晚饭。
4、until/tilluntil表示动作或状态一直持续到某一时刻，即“直到……”。
如：I will wait until/till you finish all the work. 我会等到你完成所有的工作。
（主将从现）主句用肯定句时，主句动作为持续性动作；主句用否定句时，主句动作为瞬间性动作，常用搭配not ... until “直到……才……”。
如：He waited until all the guests left. 他一直等到所有客人都走了。
The boy didn’t go to sleep until his mother came back last night. 昨晚那个小男孩直到他妈妈回来才去睡觉。
5、sincesince引导的时间状语从句常与完成时连用，表示“自从……”，而since从句部分用一般过去时。
如：I have known Bill since he was born. 从比尔出生起，我就认识他。
He has studied very hard since he came to our school. 自从来到我们学校，他学习就非常努力。
练习（一）在下列各句的空格中填入适当的连词1. ________ he was speaking, everybody listened carefully.2. Have a good look at that man ________ you pass him.3. Henry is in charge of the office ________ Mr. Smith is away.4. It was already eight o’clock ________ we got there.5. I was about to go out ________ a visitor came.6. He learned to speak German ________ he was in Berlin.7. I waited ________ he came back.8. He had learned Chinese ________ he came to China.9. ________ the work was done, we sat down to sum up experience.10. I haven’t seen him ________ he moved to the other side of the town.11. She likes everything to be in place ________ she starts to work.12. The thieves ran away ________ they caught sight of the police.13. They decided to go back home ________ their money ran out.14. ________ I get to the airport, I will phone you to pick me up.15. They were about to leave ________ it began to rain.16. He always stay in bed ________ lunch time.17. I like playing tennis ________ my younger sister prefers watching ball games.。