展开全文在高三课本第十五单元出现了下面几个句子：1AsKofiAnna，SecretaryGeneraloftheUnitedStatessaid，“eachcontribution--howsmall--canhelpmakeadifference.”2NowsheisspendingayearinremotepartofsouthwestChinaworkingasavolunteerteacherinavillageschool.这几个句子都涉及到了as的用法。作介词用，第一句话中as用作关系代词，引导定语从句，含义为“正如”，第二句话中as的含义为“作为，当作”，做介词。下面让我们结合历年高考试题对其用法进行分析。一.用作连词引导让步状语从句从句必须用倒装语序，把作表语用的名词(不加冠词)或作表语的形容词，或动词(原形)，或副词提到as前面。如：1.Childasheis，heknowsalot.2.Tiredastheywere，theystayeduplatepreparingforthecomingexams.3.Tryashewould，hefailedagainthistime.考例：1.(2005重庆)___，hetalksalotabouthisfavoritesingersafterclass.A.AquietstudentashemaybeB.QuietstudentashemaybeC.BeaquietstudentashemaybeD.Quietashemaybeastudent【解析】答案是B。作表语的是名词student，名词前不加冠词。2.(2005.广东)____，Carolina，couldn\'tgetthedooropen.A.TryasshemightB.AsshemightbeC.ShemightastryD.Mightsheastry【解析】答案是A。as引导让步状语，将动词原形try提到as前面。二.用作关系代词，引导定语从句as用作关系代词，引导定语从句，含义为“正如”。如：1.Heisverycareful，ashisworkshows.2.Asisknownisreportedinthenewspaper，talksbetweenthetwocountriesaremakingprogress.考例：(2005浙江)___Iexplainedonthephone，yourrequestwillbeconsideredatthenextmorning.A.WhenB.AfterC.AsD.Since【解析】答案是C。意思是“正如我在电话里解释的那样……”。2.(2006)TheBeatles，____manyofyouareoldenoughtoremember，camefromLiverpool.A.whatB.thatC.howD.as【解析】答案是D。引导非限制性定语从句。三.作为副词用于表示“和……一样，”的意思，as…as中间要用形容词/副词的原级，如aslongas：长达；asfaras远达；asmuchas：多达；astallas含义为“高达…”。如：Thatdaytheywalkedasfarastenkilometersintwohours.考例：(2005安徽)Johnisthetallestboyintheclass，_______accordingtohimself.A.fivefooteightastallasB.astallasfivefooteightC.asfivefooteighttallasD.astallfivefooteightas【解析】选B.as…as中间要用形容词/副词的原级。四.引导时间状语从句含义为“当…的时候”，如：1.Iwatchedherasshecombedherhair.2.Ashegrewolder，helostinterestineverythingexceptgardening.考例：1.(NMET1994)MotherwasworriedbecauselittleAlicewasill，especially____FatherwasawayinFrance.A.asB.thatC.duringD.if【解析】答案是A.“在……时候”，相当于when.而C选项是介词，不接句子。2.(MET90)_____thedaywenton，theweathergotworse.A.WithB.SinceC.WhileD.As【解析】答案是D.“随着”的意思，asthedaywenton可以作为固定结构记住。五.作介词用有“作为，当作”的意思。如：1.Theywerealldressedasclowns.他们都打扮得如小丑。考例：(2005广东)Ifeelthatoneofmymainduties_____ateacheristohelpthestudentstobecomebetterlearners.A.forB.byC.asD.with【解析】选C。“作为教师”的意思。