aswhile的用法.doc

as的用法小结 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。 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. 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. 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. Just as the flying worm hit her face, she gave a loud cry. D) 后接名词表示某一年龄段时,用as。如: As a young man, he was active in sports. 2. as=since, 作既然、由于解,引导原因状语从句,常用来表示已为人们所知或显而易见的原因或理由。如: As / Since youre not feeling well, you may stay at home. As he wasnt ready in time, we went without him. 3. as=in the way that, 作像、按照的方式解,引导方式状语从句。如: He speaks English as Americans do. Remember, you must do everything as I do. 4. 用于as.as.或not so/ as.as.中,前一个as是副词,后一个as是连词,引导比较状语从句。如: They helped the old man as often as possible. I dont speak English so/ as well as he does. 5. 作虽然、尽管解,引导让步状语从句。常用倒装语序,即adj. /adv. / n.+ as +主语+谓语+主句。如: Tired as they were, they walked on. Child as he is, he knows a lot. (child前不用冠词) 二、 as作关系代词,引导定语从句,作正如、这一点解。如: He is very careful, as his work shows. As is well-known, Taiwan belongs to China. 三、 as作介词的用法: as引导的介词短语大多用作状语,as译为作为;少数情况可引起宾语补足语。如: As a League member, Ill take the lead in everything. (状语) She works as a doctor. (状语) They have me as one of their own children.(引起宾语补足语) as还有一些固定结构：1)as well as和一样 2)as far as就来说 3)as long as只要4)as soon as一就 5)as if好像while的用法连词while大致有以下四种用法: 1.引导时间状语从句,意为当的时候;和同时,此时的主从句谓语动作同时发生,从句谓语通常是延续性动词。如: Mary watched TV while she ate her supper.玛丽边吃饭边看电视。 While she was listening to the radio, she fell asleep.她听着收音机睡着。 while引导从句时,如主从句的主语一致,且从句谓语又含有be,则从句主语和be可省略。while后可直接跟现在分词、名词、形容词或介词短语。如: We are teachers while (we are) serving as students.我们边当老师边当学生。 While (he was) yet a youth, he gained many prizes.他年轻时就曾多次获奖。 He caught a cold while(he was) on vacation.他度假时患了感冒。 2.表示对比或转折,意为而;然而。此时,while一般位于句中。如: Some people waste food while others havent enough.有些人浪费粮食,然而有些人却吃不饱。 You like sports, while I prefer music.你喜欢体育,而我更喜欢音乐。 3.表示让步,通常位于句首,意为尽管;虽然。如: While I agree with your reasons, I cant allow it.尽管我同意你的理由,但我不能允许这样做。 While he loves his students, he is very strict with them.虽然他爱他的学生,可是他对学生们很严格。 While (he was) respected, he is not liked.他虽受人尊敬,但并不被人喜欢。 4.表示条件,意为只要,其意思和用法相当于as long as。while可位于句首,也可位于句中。如: You dont have to worry while we are here.只要我们在,你就别着急。 There will be life while there is water and air.只要有空气和水,就有生命。 While there is life, there is hope.留得生命在,不怕没希望。 5.意为同时;也。如: While the book is welcomed by scholars, it will make an immediate appeal to the general readers.这本书受到学者的欢迎,同时也会引起一般读者的兴趣。 6.意为趁着。如: Make hay while the sun shines.晒草要趁阳光好。(谚) Strike while the iron is hot.趁热打铁。(谚) While the roses are yet in bloom, will you come with me to see them?趁着玫瑰花还开着,你和我一道去看看好吗 when&while两者的区别如下：（一）、when，while都有“当时候”的意思。when既可表示某一点时间，也可以表示某一段时间 。在when引导的时间状语从句中，其谓语动词可以是延续性的，也可以是非延续性的，可与主句中的谓语动词同时发生，也可在其后发生。 例如： 1、I was just reading a book when she came into my room. 她走进我房间时，我正在看书。 2、Were you writing when the teacher came in? 老师进来的时候，你在写信吗？ 3、When he was a child he was always trying out new ideas. 他小时候就常常试验一些新的设想。（二）、while只能表示某一段时间，不能表示某一点时间。在while引导的时间状语从句中，其谓语动词只能是延续性的，而且也只能与主句中的谓语动词同时发生或存在。 例如： 1、While Jim was mending his bike, Lin Tao came to see him. 正当吉姆修自行车时，林涛来看他。 2、You cant do your homework while youre watching TV. 你不能一边看电视一边做家庭作业。 （三）、另外，when和while的区别还在于：while引导的时间状语从句多用进行时态，而when引导的时间状语从句多用一般时态。 例如： 1、While they