时间状语从句
一. 概念：在复合句中，由时间连接词引导的状语从句叫做时间状语从句。
二. 种类：
1.由when, while, as引导的时间状语从句。
（1）.when引导的从句的谓语动词可以是延续性的动词，又可以是瞬时动词。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，并且when有时表示“就在那时”。
When she came in, I stopped eating.她进来时，我停止吃饭。(瞬时动词)
When I lived in the countryside, I ud to carry some water for him.当我住在农村时，我常常为他担水。（延续性的动词）
（2）while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。并且while有时还可以表示对比
While my wife was reading the newspaper, I was watching TV.
I met her while I was at school.
I like playing football while you like playing basketball.
（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。
He jumps as he goes along. 他边走边跳。
As we was going out, it began to snow.当我们出门时，开始下雪了。（铂金多少钱一克as强调句中两个动作紧接着先后发生，而不强调开始下雪的特定时间）
2.由before和after引导的时间状语从句。
before引导的时间状语从句表示主句动作发生在从句动作之前。从句不用否定的谓语形式。从句位于主句之后时，before有时译成“才；就”。还要注意主句和从句的时间关系。当主句用将来时，从句总是用现在时；从句用过去时，则主句多用过去完成时，以此来体现
动作发生的先后顺序。
after表示主句动作发生在从句动作之后，主句和从句的时间关系正好与before相反。如：
It will be four days before they come back.他们要过四天才能回来。
梦见菩萨雕像My father had left for Canada just before the letter arrived.
我父亲恰好在信到达之前去加拿大了。
苏幼珍
After we had finished the work, we went home.完成工作之后，我们回家了。
3.由till或until引导的时间状语从句。till和until一般情况下两者可以互换，但是在强调句型中多用until。并且要注意的是：如果主句中的谓语动词是瞬时动词时，必须用否定形式；如果主句中的谓语动词是延续性动词时，用肯定或否定形式都可以，但表达的意思不同。till不可以用在句首，而until可以放在句首。
I didn't go to bed until（till） my father came back.直到我父亲回来我才上床睡觉。
I worked until he came back.我工作到他回来为止。
I didn't work until he came back.他回来我这才开始工作。
4.由since引导的时间状语从句。“自从……以来”,或“自从……以后”, since引导的从句的谓语动词可以是延续性的动词，又可以是瞬时动词。主句通常用现在完成时态，从句谓语动词用一般过去时，。但在It is ＋时间＋since从句的句型中，主句多用一般现在时。
I have been in Beijing since you left. 自从你离开以来，我一直在北京了。
It is five months since our boss was in Beijing.我们老板离开北京有五个月了。
5.由as soon as, immediately, directly, instantly, the moment, the instant, the minute, 等引导的时间状语从句。这些连词都表示“一……就”。例如：
The moment I reach Canada, I will ring you up. 我一到加拿大，就给你来电话。
6.hardly(scarcely, rarely)…when / before, no sooner…than相当于复杂指令集as soon as之意。主句用过去完成时，从句用一般过去时。当hardly, scarcely, rarely和no sooner位于句首时， 主句应用倒装语序（半倒装）。
Hardly had I sat down when he stepped in.我刚坐下，他就进来了。
6.由by the time引导的时间状语从句。注意时态的变化：在一般情况下，如果从句的谓语动词用一般过去时，主句的谓语动词用过去完成时；如果从句的谓语动词用一般现在时，主句的谓语动词用将来完成时。
By the time you came back, I had finished this book.到你回来时，我已经写完这本书了。
By the time you come here tomorrow, I will have finished this work. 你明天来这儿的时候，我将已经完成此工作了。
7. .由each time\every time\next time/last time/every time/the first time,和whenever/no matter when引导的时间状语从句。
Each time he came to Shenyang , he would call on me.
8.由as long as和so long as引导的时间状语从句。（无区别）这两个连词表示“只要”.
You can go where you like as long as you get back before dark. 你可以随意到哪里去，只
要在天黑以前回来就行。
1.By the end of last term , I__A__ten books.
A had finished reading B.have finish reading
C.had finish to read D.finish read
wangwei2. I won't believe you_B__ I have en it with my own eyes.
A. before B. until C. after D. when
3.___ he came to study in the university, he has made much progress in the study of English.
A. While B. When C. Since D. After
1. It was quiet ________ tho big trucks started coming through the town.
A. before B. after C. until D. unless
2. It emed only conds ________ the boy finished washing his face.
A. when B. before C. after D. even if
3. Hardly had he reached the school gate ________ the bell rang.
A. while B. when C. as D. as soon as
4.We were told that we should follow the main road _____ we reached the central railway station.
A. whenever B. until C. while D. wherever
5. I recognized you ________ I saw you at the airport.
A. the moment B. while C. after D. once
6. He was about to go to bed ________ the doorbell rang.
A. while B. as C. before D. when
7.________I listen to your advice, I get into trouble.
A. Every time B. When C. While D. Until
宇航员英语8. _____ John was watching TV, his wife was cooking.
A. As B. As soon as C. While D. Till
9. The children ran away from the orchard(梁威果园) ______ they saw the guard.
A. the moment B. after C. before D. as
10. No sooner had I arrived home _____ it began to rain.
A. when B. while C. as D. than
11. Several weeks had gone by _____ I realized the painting was missing.
