ｗｈｅｎ，ｗｈｉｌｅ及ａｓ考点辨析when， while及as都能引导多种状语从句: 一、 when常见考点 1、“当……时候”， 引导时间状语从句 When he was a young man， he was fond of hunting. It was already 10:00PM，when I finished the work. 2、“正在那时，这时”等于and at that time，引导时间状语从句 We were having a meeting when someone broke in. Wewereabouttoleave when it began to rain. 3、“既然”等于since 或considering that， 引导原因状语从句 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、“虽然，然而，可是”引导让步状语从句。
He usually walks when 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 talk so loud while others are working. While I was cleaning the window， my finger was 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 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，引导条件状语从句。
There is hope while there is life. While you study hard， your effort will pay off. 4、“而，然而”，表对比或相反的情况 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 he works. （一边……一边） Jame’s blindness was 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 a message. 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 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.请预览后下载！ 1.（2007山东，29）_______I really don’t like art， I find his work impressive. A. AsB. SinceC. IfD. While 2. （2007北京，25） —— Where is that report ? —I brought it to you ________you were in Mr Black’s office yesterday. A. ifB. whenC. becauseD. before 3. （2007四川，29）I’d like to study law at university ________my cousin prefers geography. A. thoughB. asC. whileD. for 4. （2007重庆，34） ______ ，his idea was accepted by all the people at the meeting. A. Strange as might it sound B. As it might sound strange C. As strange it might sound D. Strange as it might sound 5.（2006广东，26）Jenny was very sad over the loss of the photos she had shot at Canada， ________this was a memory she especially treasured. A. asB. ifC. whenD. where 6. （2006山东，31）How can you expect to learn anything ________you never listen? A. in caseB. even ifC. unlessD. when 7. （2006湖南，31）I had just stepped out of the bathroom and was busily drying myself with a towel ________I heard the steps. A. whileB. when C. since D. after8. （2006辽宁，24）He was about halfway through his meal ________a familiar voice came to his ears. A. whyB. whereC. whenD. while 9. （2006天津，2） The cost of living in Glasgow is among the lowest in Britain， the quality of life is probably one of the highest. A. sinceB. whenC. asD. while 10. （2005福建，24） —— Did Jack come back early last night? — Yes. It was not yet eight o’clock ________he arrived home. A. beforeB. whenC. thatD. until 11. （2005上海，34）He transplanted the little tree to the garden ________it was the best time for it. A. whereB. whenC. thatD. until 12. （2004全国I ，35）I do every single bit of housework， ________my husband Bob just does the dishes now and then. A. sinceB. whileC. whenD. as 13. （2004全国 ，21）Don’t be afraid of asking for help ________it is needed. A. unlessB. sinceC. althoughD. when 14. （2004浙江 ，31） ________modeling business is by no means easy to get into， the good model will always be in demand. A. WhileB. SinceC. AsD. If请预览后下载！ 15. （2004江苏 ，23） ________I accept that he is not perfect， I do actually like the person A. WhileB. SinceC. BeforeD. Unless The key: 1-5DBCDA6-10DBCDB11-15BBDAA一、根据从句动作的持续性来区分 1、“主短从长”型：即主句是一个短暂性动作，而从句是一个持续性动作，此时三者都可用。
如： Jim hurt his arm while［when， as］ he was playing tennis. 吉姆打网球时把手臂扭伤了 As［When， While］ she was waiting for the train， she became very impatient. 她在等火车时，变得很不耐烦 注意：as 用于引出一个持续性动词表示“在……期间”时，其谓语通常只能是那些含有动作(action)和发展(development)意味的动词，一般不能是那些不用于进行时态的动词(如 be，seem，love，want，agree，see，know，have等)，所以下面一句中的 while 不能换为 as： A：I’m going to the post office. 我要去邮局 B：While you are there， can you get me some stamps？当你在邮局时，能帮我买几张邮票吗？ 2、“主长从长”型：即主句和从句为两个同时进行的动作或存在的状态，且强调主句动作或状态延续到从句所指的整个时间，此时通常要用while。
I always listen to the radio while I’m driving. 我总是一边开车一边听收音机请预览后下载！但是，若主句和从句所表示的两个同时进行的动作含有“一边……一边”之意时，则习惯上要用as如：He swung his arms as he walked. 他走路时摆动着手臂3、“主长从短”型：即主句是一个持续性动作，而从句是一个短暂性动作，此时可以用as或when，但不能用while如：It was raining hard when [as] we arrived. 我们到达时正下着大雨When [As] he came 。