as的用法小结(精华版)

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。①when作当……的时候解,可以指较短的(一点)时间,也可指一段时间。如:Whenhewasatcollege,hecouldspeakseveralforeignlanguages.（表示一段时间）Whentheclockstrucktwelve,allthelightsinthestreetwentout.（表示时刻）②while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:Workwhileyouwork.Playwhileyouplay.③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:Thegirldancesasshesingsonthestage.Helookedbehindfromtimetotime//ashewentforward.B)表示两个同步发展的动作或行为,译为随着……。如:Astimewenton/by,shebecamemoreandmoreworried.Aschildrengetolder,theybecomemoreandmoreinterestedinthethingsaroundthem.C)表示两个短促行为或事件几乎同时发生。如:Ithoughtofit//justasyouopenedyourmouth.Justastheflyingwormhitherface,shegavealoudcry.D)后接名词表示某一年龄段时,用as。如:Asayoungman,hewasactiveinsports.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/Sinceyou'renotfeelingwell,youmaystayathome.Ashewasn'treadyintime,wewentwithouthim.3.as=inthewaythat,作像、按照……的方式解,引导方式状语从句。如:HespeaksEnglishasAmericansdo.Remember,youmustdoeverythingasIdo.4.用于as...as...或notso/as...as...中,前一个as是副词（副词后面跟形容词、动词、副词）,后一个as是连词（连词后面可以跟动词、形容词、句子）,引导比较状语从句。如:Theyhelpedtheoldmanasoftenaspossible.Idon'tspeakEnglishso/aswellashedoes.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:Tiredastheywere,theywalkedon.Childasheis,heknowsalot.(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:Heisverycareful,ashisworkshows.Asiswell-known,TaiwanbelongstoChina.as的这种用法,请看2001年的高考题:isknowntoeverybody,themoontravelsroundtheearthonceeverymonth.A.ItB.AsC.ThatD.What字母下划横线的为正确答案)另外,当先行词被thesame,such等词修饰时,常用as来引导定语从句。如:Suchacleverboyashecanlearnanythingquickly.Iwasreadingthesamebookasheboughtyesterday.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:AsaLeaguemember,I'lltaketheleadineverything.(状语)Sheworksasadoctor.(状语)Theyhavemeasoneoftheirownchildren.(引起宾语补足语)