as表示“当……时候”时对谓语动词的限制

发布时间:2022-05-21T10:02:17 英语语法

as表示“当……时候”时对谓语动词的限制

有这样一道题,该选as还是when?

“I’m going to the post office.” “_________ you’re there, can you get me some stamps?”

A. As                       B. While                  C. Because               D. If

【分析】此题从句意看,as 和 while 均可以填,因为它们均可用来引导时间状语从句,表示“当……的时候”,于是一些同学便随便从as、while中选择一项。结果是:选as者错误,选while者正确。为什么呢?因为 as 和 while 在引导时间状语从句表示“当……的时候”时,有这样一个区别:as 所引导的从句谓语通常应是那些表示动作或发展意义的动词,不能是be (是,在), have (有),like (喜欢),belong (属于)等表示状态或静态意义的动词;而 while 则无此限制。所以此题的最佳答案是B而不是A。请再看以下考题,答案也选 while,不选as:

(1) _________ you are at home alone, please don’t leave the door open.

A. While                   B. As                        C. Before                  D. How

(2) _________ you are alone with her, tell her that you like her.

A. While                   B. As                        C. After                    D. How

不过顺便说一句,以上关于 as 的用法限制是针对它引导时间状语从句时而言的,它若引导原因状语从句,则无此限制。如:

As he is young, we can’t be too hard on him. 由于他还年轻,所以我们不能对他太苛刻。

As the wages were low, there were few applicants for the job. 因为工资低,没有什么人申请这份工作。

The teacher told him to leave as he was a disturbance to the other students. 因为他干扰了其他学生,所以老师叫他出去。