请给讲一下 as .....as ......的用法

as可以作连词、介词及关系代词。现将其用法小结如下:

一、 as作连词的用法:

1. 作"当……的时候",引导时间状语从句。注意与when、 while的用法区别。

① when作"当……的时候"解,可以指较短的(一点)时间,也可指一段时间。如:

When he was at college, he could speak several foreign languages.

When the clock struck twelve, all the lights in the street went out.

② while常表示一段较长的时间或一个过程,强调主句谓语动词与从句谓语动词同时发生。如:

Work while you work. Play while you play.

③ 但属下列情形时,只用as, 而不用when或while。

A) 用于表示同一个人的两种动作交替进行,指"一边……,一边……"。如:

The girl dances as she sings on the stage.

He looked behind from time to time as he went forward.

B)表示两个同步发展的动作或行为,译为"随着……"。如:

As time went on / by, she became more and more worried.

As children get older, they become more and more interested in the things around them.

C)表示两个短促行为或事件几乎同时发生。如:

I thought of it just as you opened your mouth.

Ju