浅谈时间状语从句

在第九单元，我们学习了由when引导的时间状语从句，同学们都掌握了吗？引导时间状语从句的引导词除了有when之外，还有while，as，as soon as，before，after，since，until等，我们一起来学习一下吧！

1． when意为“当……时”，引导的从句表示主句的动作和从句的动作同时发生。例如：

She began to learn English when she was five years old.

她五岁时开始学英语。

I will tell her when she comes back.

她回来时我会告诉她的。

由when引导的时间状语从句，主句的谓语动词是一般将来时时，从句的谓语动词要用一般现在时表示将来。

2． while意为“当……时，在……的过程中”。从句通常要用进行时，如果主句和从句的动作是两个同时进行的长时间的动作，那么主句也要用进行时。例如：

While we were having the English class, Li Ming came in.

当我们在上英语课时，李明进来了。

While my mother was cooking supper, I was watching TV.

当妈妈在做晚饭的时候，我正在看电视。

3． as意为“当……时，一边……一边”，引导的时间状语从句常常用来强调主句和从句的动作同时发生，此时when和while不常用。例如：

As the students walked along the lake, they sang happily.

学生们一边沿着湖走，一边快乐地唱着歌。

Will you please take a message for Mary as you go past her room?

你路过玛丽房间时，请给她捎个口信好吗？

由when, while, as引导的时间状语从句都可以表示“当……时”又发生了什么事情。用when时不强调动作的长短；用while时通常用进行时表示较长的动作；由as引导时通常强调较短的动作。

4． as soon as意为“一……就”，引导的时间状语从句在用法上要特别注意时态。例如：

The film began as soon as we got to the cinema.

我们一到电影院，电影就开始了。

She will tell you the news as soon as she sees you.

她一见到你就会告诉你消息。

如果主句用一般将来时或过去将来时，那么从句要用一般现在时或一般过去时表示一般将来时或过去将来时。

5． before意为“在……以前”，引导的时间状语从句一般表示主句的动作发生在从句动作之前。例如：

Don’t close the windows before you go to bed.

睡觉之前不要关窗户。

I didn’t know any English before I went to the middle school.

我上中学之前对英语一无所知。

6． after意为“在……之后”，引导的从句一般表示主句的动作发生在从句的动作之后。例如：

After she locked the door, she left.

她锁好门之后，离开了。

7． since意为“自……以来”，引导的时间状语从句用法上要注意时态：从句的谓语动词表示动作的起点，用一般过去时；主句的谓语动词表示动作从开始以来延续至今，一般用现在完成时。如果主句表示的不是延续性的动作，而是表示目前的情况，可以用一般现在时。例如：

It is three years since she joined the League.

她入团3年了。

She has studied in this school since she came to Beijing.

自从她来北京后，就在这所学校学习。

8． until意为“直到……”，引导的从句，如果主句的谓语动词是延续性动词，主句和从句都用肯定式。如果主句的谓语动词是非延续性动词，主句用否定式，从句用肯定式，not...until表示“直到……才”。例如：

We worked until it was dark.

直到天黑我们还在工作。

He didn’t go home until he finished his homework.

直到完成作业他才回家。

【跟踪练习】

1. He will write to you as soon as he______to Shanghai.

A. gets B. is getting

C. will get D. shall get

2. ______ mother got home, I was tidying my room.

A. After B. When

C. As soon as D. Before

3. The teacher didn’t begin her class______ the students stopped talking.

A. until B. because

C. after D. when

4. You must make your new house clean and safe______you move in.

A. because B. when

C. before D. until

5. As soon as he saw me, he ______ to speak to me.

A. stops B. stopped

C. was stopping D. is stopping

6. It______hard when I got to the factory this morning.

A. is raining B. rained

C. was raining D. rains

7. Will you come and stay with us for a while when you______doing your homework?

A. will finish B. is finishing

C. finished D. finish

Key:1． A 2. B 3. A 4. C 5. B 6. C 7. D