要点精析一、名词性从句的句法功能名词性从句在句法上相当于一个名词,因此,它可以作为句子的主语、宾语、表语,以及名词的同位语。1.主语从句That_the_earth_goes_around_the_suniscertain.地球围绕太阳转是确定无疑的。Who_will_be_the_next_president_of_our_countryisstillhardtosay.谁将成为我们国家的下任总统很难说。有时为了避免头重脚轻,用it充当形式主语,把主语从句放到句末。Itisstillhardtosaywho_will_be_the_next_president_of_our_country.谁将成为我们国家的下任总统很难说。Itisapitythat_you_missed_such_a_wonderful_match.你错过了观看如此精彩的比赛真遗憾。另外,如果从句是一个完整的句子,仍要用that引导,不可省略。That_the_earth_is_roundisknowntoall.众所周知,地球是圆的。例(2010·成都外国语学校模拟)________childrenwatchandlearnfromthepeoplearoundthemhelpsthemtofigureouthowtheworldworks.A.WhichB.ThatC.HowD.What解析:考查主语从句。句意:孩子们通过观察和向周围的人学习来了解周围的世界是如何运作的。句中动词watch和learn缺少宾语,因此空白处应填what。答案:D2.宾语从句Weallknowthat_the_earth_is_round.我们都知道地球是圆的。Wesupposethat_running_water_is_pure_and_clean.我们认为自来水很纯净。宾语从句也常由it替代,真正的宾语放在句尾。Wetakeitforgrantedthat_running_water_is_pure_and_clean.我们认为自来水很纯净。Ihateitwhen_people_smoke_before_me.我厌恶人们在我面前抽烟。例(2009·北京)Atfirsthehatedthenewjobbutdecidedtogivehimselfafewmonthstosee________itgotanybetter.A.whenB.howC.whyD.if解析:考查宾语从句。句意:一开始他不喜欢这份新工作,但还是决定给自己几个月的时间来看一看是否情况会有好转。从句中不缺少时间、地点、原因,排除A、B、C三项。D项表示“是否”,符合题意。答案:D3.表语从句Theproblemisthat_we_don't_have_much_time_left.问题是我们剩下的时间很少。Myquestioniswho_is_responsible_for_all_this.我的问题是谁对这事负责。例(2010·江苏泰兴市朝中调研)—DoyouthinkitwiseforChinesemotherstotrytodoeverythingfortheirchildren?—No,that's________theyaremistaken.A.whereB.whenC.soD.how解析:考查表语从句。where引导表语从句,表示那就是她们的错误所在。答案:A4.同位语从句同位语从句用来解释说明前面的名词,通常由本身无意义的连词that引导,通常不可省略。一般在fact,news,idea,hope,doubt,fear,belief,dream,plan,advice,suggestion,decision等名词后有同位语从句,具体说明这些名词的内容。Wewereshockedatthenewsthat_dozens_of_miners_were_killed_in_this_mine_accident.许多名矿工死于矿难,我们对这个消息感到震惊。Wordcamethattherewouldbeanotherhurricanecoming.据说将会有另一场飓风。Thereisnodoubtthat_he_is_the_best_person_for_this_position.毫无怀疑,他是这个位置的最佳人选。例(2009·江西)Thefacthasworriedmanyscientists________theearthisbecomingwarmerandwarmertheseyears.A.whatB.whichC.thatD.though解析:本题考查同位语从句。句意:近年来全球气候不断变暖,这一事实使得很多科学家感到担忧。该题同位语从句结构完整,故选连词that。答案:C二、名词性从句的连接词名词性从句由从属连词引导,有如下几类:1.由本身没意义但在从句中不充当任何语法成分的连词that引导。HetoldmethathewouldcometovisitusonSunday.他告诉我他将在星期天来拜访我们。Theteachersuggestedthatthestudentsbuythebooks.这个老师建议学生买这些书。2.由具有意义但在从句中不担当成分的连词whether或if引导。Idon'tknowwhetherhewillgowithusornot.我不知道他是否和我们一块去。HeaskedmewhetherIwouldaccepthimasanewmember.他问我是否能把他作为一名新成员接受他。例(2010·海淀模拟)Kevinconsultedhisteacherabout________heshouldstudyabroadaftergraduation.A.whetherB.whereC.whenD.that解析:句意:Kevin就毕业后是否应该去国外学习征求了老师的意见。whetherheshouldstudyabroadaftergraduation作介词about的宾语。where与句中的abroad矛盾;when与句中的aftergraduation重复;that引导的宾语从句一般不作介词的宾语。答案:A3.由带疑问意义的连接副词或连接代词who,when,where,how,which,whose等引导。Idon'tknowwhowilltakehisplaceifheleaves.我不知道如果他离职谁将接替他。WeallknowwhenandwherethenextOlympicGameswillbeheld.我们都知道下届奥运会将在何时何地举办。4.由连接代词what引导。Idon'tknowwhathereallylikes.我不知道他到底喜欢什么。Whathesaidprovedtrue.他所说的被证实是真的。what作为连接代词,承担两重任务:连接句子和代替从句缺少的成分(可以代替从句主语、宾语和表语)。WhatIwantforthemomentisacar.(主语从句中,what是want的宾语)我此刻想要的是一辆汽车。Whatisleftundonewillbecarriedonbyus.(主语从句中what是主语)未做完的工作将由我们继续做。Thecitytodayisnolongerwhatitwas5yearsago.(表语从句中,what是表语)今天的这个城市不再是它5年前的样子了。what在句子中除了可以代物(something),还可以代人、时间、地点等。Pleasetellmewhatyouwant./Pleasetellmethethingthatyouwant.(what指物)请告诉我你想要什么。Heiswhatisknownaswalkingdictionary,forheknowseverywordyoudon'tknow./Heisthepersonthatisknownasawalkingdictionary,forheknowseverywordyoudon'tknow.(what指人)他就是人们所知的活字典,因为每个你不认识的字他都认识。Afteralongjourney,theyfinallyarrivedatwhatisnowBoston./Afteralongjourney,theyfinallyarrivedattheplacethatisnowBoston.(what指地点)经过长途跋涉,他们终于到达今天的波士顿。Afterwhatseemedhoursofwaiting,itwasfinallymyturn./Afteraperiodoftimethatseemedhoursofwaiting,itwasfinallymyturn.(what指时间)等待了像是几个小时之后,最后终于轮到我了。例(2009·江苏)ManyyoungpeopleintheWestareexpectedtoleave________couldbelife'smostimportantdecision—marriage—almostentirelyuptoluck.A.asB.thatC.whichD.what解析:考查名词性从句。宾语从句中缺少主语,因此选择what。答案:D