when，while，as考點(diǎn)辨析

　　when,while,as都能引導(dǎo)多種狀語(yǔ)從句：

　　一、when常見(jiàn)考點(diǎn)

　　1、“當(dāng)……時(shí)候”,引導(dǎo)時(shí)間狀語(yǔ)從句。

　　When he was a young man，he was fond of hunting. It was already 10：00PM，when I finished the work.

　　2、“正在那時(shí)，這時(shí)”等于and at that time，引導(dǎo)時(shí)間狀語(yǔ)從句。

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

　　3、“既然”等于since 或considering that， 引導(dǎo)原因狀語(yǔ)從句。

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

　　4、“雖然，然而，可是”引導(dǎo)讓步狀語(yǔ)從句。

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

　　二、while常見(jiàn)考點(diǎn)

　　1、“當(dāng)……時(shí)候”， 引導(dǎo)時(shí)間狀語(yǔ)從句(從句動(dòng)作必須是延續(xù)性的)。

　　Please don't talk so loud while others are working. While I was cleaning the window，my finger was seriously cut.

　　2、“雖然，盡管”相當(dāng)于although，引導(dǎo)讓步狀語(yǔ)從句(常把while放在句首)。

　　While she is a top student， she has some shortcomings. While the Internet is bridging the distance between people， it may also be breaking some home or will cause other family problems.

　　3、“只要，如果”等于as long as，引導(dǎo)條件狀語(yǔ)從句。

　　There is hope while there is life. While you study hard， your effort will pay off.

　　4、“而，然而”，表對(duì)比或相反的情況。

　　He likes pop music，while I am fond of folk music. Kids talk frequently about what they can do，while many adults do the opposite， tending to talk about what they can't .

　　三、as常見(jiàn)考點(diǎn)

　　1、“一邊……一邊”或“隨著……”，引導(dǎo)時(shí)間狀語(yǔ)從句(as引導(dǎo)的從句內(nèi)部的動(dòng)作與主句內(nèi)動(dòng)作同步)。

　　John sings as he works. (一邊……一邊)

　　Jame‘s blindness was getting worse as he was getting older.(隨著……)

　　2、“因?yàn)?rdquo;， 引導(dǎo)原因狀語(yǔ)從句。

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

　　3、“盡管，即使，雖然” 引導(dǎo)讓步狀語(yǔ)從句(用于形容詞，副詞或名詞后構(gòu)成部分倒裝)。

　　Young as I am， I already know what career I want to follow. Much as I like you， I couldn't live with you. Child as Tom is ， he has been a success.