在复合句中起名词作用的从句叫做名词性从句。名词性从句主语从句表语从句宾语从句同位语从句连接代词who,whom,whose,which,what,whatever连接副词how,why,when,wherehowever,wherever连接词that,whether,if,becauseasif/asthough(不充当从句的任何成分)引导名词性从句的关联词在名词性从句中一律用陈述句的语序,即使从句表达的是疑问含义。Theproblemiswhathehasdonetothelittleboy.问题是他对那个小男孩做了些什么。1.主语从句在句中作主语的句子叫主语从句。主语从句通常由从属连词that,whether和连接代词what,who,which,whatever,whoever以及连接副词how,when,where,why等词引导。that在从句中无词义,只起连接作用;连接代词和连接副词在句中既保留自己的疑问含义、又起连接作用,在从句中充当成分。Whathewantstotellusisnotclear.他要跟我们说什么,还不清楚。Whowillwinthematchisstillunknown.WheretheEnglisheveningwillbeheldhasnotyetbeenannounced.Thathestoleabikewastrue.单个的主语从句作主语时,谓语动词用单数形式。如果是两个或两个以上的主语从句作主语,谓语动词则用复数形式。Whereandwhenhewasbornhasnotbeenfound.Whenthepersonwasmurderedandwhyhewasmurderedarestillunknown.有时为避免句子头重脚轻,常用it代替主语从句作形式主语放于句首,而把主语从句置于句末。主句的谓语动词一般用单数形式。常用句型如下:1)It+be+名词+that从句2)It+be+形容词+that从句3)It+be+动词的过去分词+that从句4)It+不及物动词+that从句Itisknowntoushowhebecameawriter.我们都知道他是如何成为一名作家的。注意:在主语从句中用来表示惊奇、不相信、惋惜、理应如此等语气时,谓语动词要用虚拟语气“(should)+do”,常用的句型有:ItisnecessaryIt’simportant,It’snaturalstrange,etc.)that…2.宾语从句名词句用作宾语的从句叫宾语从句。引导宾语从句的关联词与引导主语从句表语从句的关联词大致一样,在句中可以作谓语动词或介词及非谓语动词的宾语。1.)由连接词that引导的宾语从句由连接词that引导宾语从句时,that在句中不担任任何成分,在口语或非正式的文体中常被省去,但如从句是并列句时,第二个分句前的that不可省。HehastoldmethathewillgotoShanghaitomorrow.注意:在demand,order,suggest,advise,decide,insist,desire,request,command等表示要求、命令、建议、决定等意义的动词后,宾语从句常用“should+动词原形”。Iinsistthatshe(should)doherworkalone.Thecommanderorderedthattroops(should)setoffatonce.但是,如果suggest作“表明、暗示”讲,insist作“坚持说、坚持认为”讲,则其后的宾语从句中应该用陈述语气。Thesmileonhisfacesuggestedthathehadpassedtheexamination.Iwanttoknowwhathehastoldyou.Shealwaysthinksofhowshecanworkwell.Shewillgivewhoeverneedshelpawarmsupport.3)用whether或if引导的宾语句whether和if均可引导动词后的宾语从句,常可互换。但从句中有ornot时或介词后的宾语从句中只能用whether连接。其它名词性从句,如:主语从句、表语从句、同位语从句只用whether.Everythingdependsonwhetherwehaveenoughmoney.Idon’tcareaboutwhetheryouhavemoneyornot.介词后的宾语从句一般不用which和if引导,要用whether和what。that也很少引导介词宾语从句,只在except,but,besides等之后才用。4)宾语从句中的时态呼应宾语从句的谓语动词时态受主句谓语动词的影响,如果主句的谓语动词是一般现在时从句中的谓语动词可以用各种时态;IknowthathestudiesEnglisheveryday.Iknow(that)hewillstudyEnglishnextyear.WeallknowthathehasstudiedEnglishsince1998.IknowthathestudiedEnglishlastterm.如果主句中的谓语动词用了一般过去时,则从句中的语动只能用过去时的某种形式,如一般过去时,过去进行时,过去将来时等;Webelievedthathehadearnedenoughmoneytobuildahouse.TheteachertoldusthatTomhadleftusforAmerica.当从句表示的是客观真理,科学原理,自然现象,则从句仍用现在时态。Theteachertoldusthatthesunrisesintheeast.5)当主句是I/Wethink(suppose,expect,believe,guess,imagine)时,其后的宾语从句如果是否定形式,常把否定词not从从句中转移到主句中成为否定的转移。Wedon’tbelievethathewillwinthegame.Idon’tthinkhewilldoso.doubt用于肯定结构时,后面用whether/if引导名词性从句;用于否定结构或疑问结构时,后面用that引导名词性从句。besure用于肯定句或疑问句时,后接that引导的名词性从句;用于否定句时,后接whether/if引导的名词性从句。连接代词whoever,whatever,whichever可引导名词性从句,相当于anyonewho,anythingthat等。它们也可以引导让步状语从句,相当于nomatterwho/what/which。Whoeverbreaksthelawshouldbepunished.3.表语从句在句中作表语的句子叫表语从句。引导表语从句的关联词与引导主语从句的关联词大致一样,表语从句位于连系动词后,有时用asif,because引导。其基本结构为:主语+系动词+that从句Thefactisthatwehavelostthegame.That’sjustwhatIwant.Thisiswhereourproblemlies.Thatiswhyhedidn’tcometothemeeting.Itlooksasifitisgoingtorain.Thisisbecausehemissedthetrainbyoneminute.需要注意的是,当主语是reason时,表语从句要用that引导而不是because。Thereasonwhyhewaslatewasthathemissedthetrainbyoneminutethismorning.4.同位语从句同位语从句说明其前面的名词的具体内容。同位语从句一般跟在某些表示抽象概念的名词后,如news,idea,information,fact,hope,thought,belief等,用来说明名词所表示的具体内容,引导同位语从句的连接词通常有that,whether和连接副词when,where,why,how;连接代词who,what,whose,which通常不引导同位语从句。Ihavenoideawhenshewillbeback.同位语从句和定语从句的区别:that作为关系代词,可以引导定语从句,充当句子成分,在从句中作宾语时可以省略;that引导同位语从句时,起连词的作用,没有实际意义,不充当句子成分,一般不能省略。Ihadnoideathatyouwerehere.Haveyougottheidea(that)thisbookgivesyouoflifeinancientGreece?(that引导同位语从句,不能省略)(that引导定语从句,作宾语,可以省略)1.Thephotographswillshowyou____.(MET1989)A.whatdoesourvillagelooklikeB.whatourvillagelookslikeC.howdoesourvillagelooklikeD.howourvillagelookslike2.考查引导词that与what的区别高考题例示:1.______wecan’tgetseemsbetterthan______wehave.(NMET1996)A.What;whatB.What;thatC.That;thatD.That;what2.Noonecanbesure_____inamillionyears.(MET1991)A.whatmanwilllooklikeB.whatwillmanlooklikeC.manwilllooklikewhatD.whatlookwillmanlike3.考查it在名词性从句中作形式主语或形式宾语的用法高考题例示:1._____isafactthatEnglishisbeingacceptedasaninternationallanguage.(NMET1995)A.ThereB.ThisC.ThatD.It6.考查名词性从句的虚拟语气问题高考题例示:1.Itisnecessarythatacollegestudent______atleastaforeignlanguage.(上海1993)A.mastersB.shouldmasterC.masteredD.willmaster