专升本英语常见考点：即难点易错点之when 和while以及as的辨析

一、when常见考点

1、“当……时候”,引导时间状语从句。

When he was a youngman，he was fond of hunting. It was already 10：00PM，when Ifinished the work.

2、“正在那时，这时”等于andat that time，引导时间状语从句。

We were having ameeting when someone broke in. We were about to leave when it began to rain.

3、“既然”等于since 或consideringthat，引导原因状语从句。

It was foolish ofyou to take a taxi，when you should easily walk there in five minutes. How can theylearn anything when they spend all their spare time watching TV?

4、“虽然，然而，可是”引导让步状语从句。

He usually walkswhen he might ride. They had only three chairs when they need five.

二、while常见考点

1、“当……时候”， 引导时间状语从句(从句动作必须是延续性的)。

Please don’t talkso loud while others are working. While I was cleaning the window，my fingerwas seriously cut.

2、“虽然，尽管”相当于although，引导让步状语从句(常把while放在句首)。

While she is a topstudent， she has some shortcomings. While the Internet is bridging the distancebetween people， it may also be breaking some home or will cause other familyproblems.

3、“只要，如果”等于aslong as，引导条件状语从句。

There is hope whilethere is life. While you study hard， your effort willpay off.

4、“而，然而”，表对比或相反的情况。

He likes pop music，while I amfond of folk music. Kids talk frequently about what they can do，while manyadults do the opposite， tending to talk about what they can’t .

三、as常见考点

1、“一边……一边”或“随着……”，引导时间状语从句(as引导的从句内部的动作与主句内动作同步)。

John sings as heworks. (一边……一边)

Jame‘s blindnesswas getting worse as he was getting older.(随着……)

2、“因为”， 引导原因状语从句。

As you weren‘t there， I left amessage. Perhapshe will need some help as he was ill.

3、“尽管，即使，虽然” 引导让步状语从句(用于形容词，副词或名词后构成部分倒装)。

Young as I am， I alreadyknow what career I want to follow. Much as I like you， I couldn’tlive with you. Child as Tom is ， he has been a success.