Time Clause

Time Clause

A. 引导词：

常用：when、while、as、after、before、since、until、as soon as、by the time 特殊：the minute, the moment, the second, every time, the day，the instant, immediately, directly, no sooner … than, hardly …when, scarcely … when

* 在时间状语从句中，主句是将来时的时候，从句要用一般时。

1. when当...的时候

Mozart started writing music when he was four years old.

2. while当...的时候

He visited a lot of places while he was traveling.

3. as当...的时候

He smiled as he stood up.

4. after在...之后

He leaves the classroom after he finishes his homework.

5. before 在...之前

Mr. Brown had worked in a bank for a year before he came here.

6. since 自…以来

表示从过去的一个起点时间到目前(说话时间)为止的一段持续时间。主句一般用现在完成时，从句用一般过去时。

Mr. Green has taught in that school since he came to China three years ago.

7. until 直到

They walked till /until it was dark.

Xiao Ming didn’t leave home until his father came back.

8. as soon as 一...就...

We began to work as soon as we got there.

I will write to you as soon as I get home.

9. by the time 到…为止(主句应用完成时)

By the time he got there, his father has already gone.

By the time I got to school, the class had already begun.

1.由when, while, as引导的从句

When you think you know nothing, then you begin to know something.

当你以为自己一无所知的时候，你就是在开始知道一些事物了。

When truth is buried under the ground it grows, it chokes, it gathers such an explosive force that on the day it bursts out , it blows up everything with it. 当真理被埋在地下的时候，它在生长，它感到压抑，它蓄存着这么一种爆炸性力量，一旦冒出，它就会炸破一切！

Strike while the iron is hot. 趁热打铁。

You can feel the air moving as your hand pushes through it.

当你的手在空气中挥动的时候，你就能感觉到空气在流动。

Our headmaster laughed as she spoke.

when, while和as的区别

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。并且when 有时表示“就在那时”。

When she came in, I stopped eating.

When I lived in the countryside, I used to carry some water for him.

We were about to leave when he came in.

while引导的从句的谓语动作必须是延续性的，并强调主句和从句的动作同时发生。并且while有时还可以表示对比。

While my wife was reading the newspaper, I was watching TV.

I like playing football while you like playing basketball.

as引导的动作是延续性的动作，一般用于主句和从句动作同时发生。

We always sing as we walk.

As we was going out, it began to snow.

2.由before和after引导的从句

当主句用将来时，从句总是用现在时；如果before引导的从句谓语用的是过去时，则主句动词多用过去完成时。after主句和从句的动作的时间关系与before引导的从句相反。It will be four days before they come back.

Einstein almost knocked me down before he saw me.

My father had left for Canada just before the letter arrived.

They had not been married four months before they were divorced.

After you think it over, please let me know what you decide.

After we had finished the work, we went home.

3.由since引导的从句

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。一般情况下，从句谓语动词用一般过去时，而主句的谓语动词用现在完成时。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.

Where have you been since I last saw you?

It is four years since my sister lived in Beijing.

It is five months since our boss was in Beijing.

a. It is since从…以来多长时间了

It is five years since we met last time.

b. It is before…...才

It was a long time before I went to sleep again.

It was an hour before the police arrived.

4.由until引导的从句

I didn't go to bed until my father came back.

It was not until the meeting was over that he began to teach me English.

I worked until he came back.

I didn't work until he came back.

Please wait until I arrived.

5.由by the time引导的从句

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；如果主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.

By the time you come here tomorrow, I will have finished this work.

6.由as soon as, immediately, directly, instantly, the moment, the instant, the minute等引导的从句。这些连词都表示“一…就”

I will go there directly I have finished my breakfast.

The moment I heard the news, I hastened to the spot.

As soon as I reach Canada, I will ring you up.

* hardly (scarcely, rarely)…when / before, no sooner…than相当于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。

He had no sooner arrived home than he was asked to start on another journey.

No sooner had the sun shown itself above the horizon than he got out of bed to commence work.

Hardly had I sat down when he stepped in.

He had hardly fallen asleep when he felt a soft touch on his shoulder.

7.由each time, every time和whenever引导的从句

Each time he came to Harbin, he would call on me.

Whenever that man says “To tell the truth”, I suspect that he's about to tell a lie.

You grow younger every time I see you.