时间状语从句的引导词
when, before, after, as, while, till/until, since，whenever
时间状语从句的用法
时间状语从句的引导词所表示的意思不尽相同，要注意把握不同的时间状语从句的引导词所表示的不同时间关系，以及它在具体句子中对应的对应时态、语态等问题。
1. when、as、while引导的时间状语从句分析：
(1) when引导时间状语从句时表示“当……的时候”，when既可以指时间段也可指时间点，从句中既可用短暂性动词又可用延续性动词qs是什么意思，且动作既可和主句的动作同时发生又可在主句的动作之前或之后发生。
注意体会如下例句：韩语一对一培训
I’ll call you when I get there.
我一到那里就给你打电话。
When the wind blows, all the doors rattle.
只要风一吹，这门就吱嘎作响。
When I came home my wife was cooking dinner. 我回家时，妻子在做晚饭。
如果when引导的时间状语从句的主语与主句主语相同，而从句的谓语又是be动词时，那么从句中的主语和be可以省略;当when引导的时间状语从句的主语与主句主语相同时，往往还可以用“when+分词”的形式替代该状语从句。例如：
When (you are) in trouble, ask her for help.
当你遭遇麻烦的时候去向她求助。
加拿大阿尔伯塔大学排名
When I came into the room (=When coming into the room), I found him lying there asleep. 英语好词好句
当我进入房间的时候，我发现他躺在那儿睡着了。
(2) while引导时间状语从句时表示“当……的时候”，它强调主句的动作与从句的动作同时持续地进行，用于这一用法时while引导的时间状语从句和主句中的谓语动词必须是延续性动词，或者主句的动作发生在从句动作的进行过程中，主句中的谓语动词通常是非延续性动词，例如
Study while you study; play while you play.
该学习的时候就学习，该玩的时候就玩。
I met her while I was at school.
当我在学校的时候我遇见了她。
(3) as引导时间状语从句时表示“当……时，一边……一边……”，侧重表示两个动作同时发生(包括一个主语同时进行两个动作)，或者一种动作随着另一种动作的变化而变化。例如：
He jumps as he goes along. 他边走边跳。
I slipped on the ice as I ran home.
我跑回家时在冰上滑了一跤。
As the wind ro the noi incread.
刮风的时候噪声增大。
[考题1] I had just steeped out of the bathroom and was busy drying mylf with a towel ____ I heard the steps.
A. while B. when C. since D. after
[考题2] He was about halfway through his meal ____ a familiar voice came to his ears.
A. why B. where C. when D. while
[考题3] We were swimming in the lake ____ suddenly the storm started.
A. when B. while C. until D. before
alligator
[考题4] — I’m going to the post office.
— ____ you’re there, can you get me some stamps?
A. As B. While C. Becau D. If
[考题5] I ____ along the street looking for a place to park when the accident ____.
A. went; was occurring B. went; occurred
C. was going; occurred D. was going; had occurred
2. before和after 引导的时间状语从句分析：
before先看引导时间状语从句时表示主句的动作发生在从句动作之前，大学生英语
after引导时间状语从句时表示主句的动作发生在从句动作之后。例如
See me before you leave. 在你离开之前来见我。
Before they drive any of the bus, they will have to pass a special test.
在驾驶公共汽车之前，他们必须通过专门测验。
I saw them after I arrived.
在我抵达之后，我见到了他们。
I found his pen after he has left.
在他走后，我找到了他的笔。
[杜甫简介英文考题6] He was told that it would be at least three more months ____ he could recover and return to work.
A. when B. before C. since D. that
[考题7] It was some time ____ we realized the truth.
A. when B. until C. since D. before
英语学习教程3. till和 until 引导的时间状语从句分析：
till和 untilgraph arch这两个词作连词和介词时的意义和用法相同，一般可以换用(放在句首时通常用until的形式，till在口语中更为常见)。例如：
