初中主語從句講解

主語從句名詞性從句包括：主語從句、表語從句、賓語從句和同位語從句。引導(dǎo)名詞性從句的連詞有：

A.連詞：that,whether,if（這三個詞都不作從句的成分，同時，that無含義，而whether和if都表“是否”）

B.疑問代詞：who,whom,whose,what,which

C.疑問副詞：when,where,why,how（一）主語從句：在復(fù)合句中充當(dāng)主語的從句。1.that引導(dǎo)主語從句

that引導(dǎo)主語從句時不同于其他的連詞，既無詞義也不作成分，只起單純的連接作用，且通常不可以省。為了強調(diào)that引導(dǎo)的主語從句而置之于句首時，that不可省。

①Thatthedrivercouldnotcontrolhiscarwasobvious.很明顯司機不能控制住他的車了

②Thatshewaschosenmadeusveryhappy.她被選上讓我們很高興

③Thathewillcomeiscertain.他要來已經(jīng)千真萬確了★通常，that引導(dǎo)主語從句時用it做形式主語，把從句置于句尾，此時that有時可省。例如：

①Itwasobviousthatthedrivercouldnotcontrolhiscar.很明顯司機不能控制住他

②Itmadeusveryhappythatshewaschosen.她被選上讓我們很高興

③Itiscertainthathewillcome.他要來已經(jīng)千真萬確了★如果以that從句為主語的句子是疑問句，就只能用先行詞it結(jié)構(gòu)。例如：

①Isitcertainthathewillcome?

②Isittruethathewouldtaketherisk?▲it做形式主語有以下幾種不同的結(jié)構(gòu)：

(1)It+be+形容詞+that-從句

①Itislikelythathewillcome.他可能會來

②Itisstrangethatshehasevertrustedhim.她相信他，真令人奇怪

(2)It+be+名詞+that-從句

Itiscommonknowledgethatthewhaleisnotafish.鯨魚并不是魚，這是常識

It'sapitythatheshouldhave?catchedthetrain.(3)It+be+-ed分詞+that從句

Itissaidthatheisafamouswriter.據(jù)說他是個著名作家

Itisreportedthattherewillbeastormthisafternoon.據(jù)報道下午將有一場暴風(fēng)▲在表示建議、要求、命令等意義的被動結(jié)構(gòu)中，that從句中的謂語動詞常用(should)do。（參見虛擬語氣部分）

Itissuggestedthatthemeeting(should)beheldthisafternoon.會議被建議在下午舉行

Itisdemandedthathe(should)leaveatonce.他被要求立即離開(4)It+seem/happen/appear等不及物動詞+that從句。

Itseemsthatheiswrong.看起來似乎他錯了

Itappearsthattheyareinneedofhelp.看起來他們需要幫助2.whether引導(dǎo)主語從句，意為“是否”，只起連接作用，不充當(dāng)任何成分。（置于句首時必須用whether引導(dǎo)，置于句尾時，間或可用if。）

Whetherhewillwinthegameisnotclear.他是否會贏得比賽還不清楚。

Whetherhewillcomeisuncertain.他是否會來還不確定

Itisnotclearwhether/ifhewillcome.

Itwasuncertainwhetherhewouldcome.3.連詞代詞what,who,which,whose等引導(dǎo)的主語從句。這些連接代詞作用相當(dāng)于代詞，在從句中擔(dān)當(dāng)主語、賓語、表語、定語等。

Whatweneedismoretime.我們需要的是更多時間

Whowasresponsiblefortheaccidentisnotyetclear.誰應(yīng)該對這場事故負(fù)責(zé)還不清楚。

Whosebookitisnotimportant.這是誰的書并不重要。

Whichschoolyouwanttogomattersmuch.你想去哪所學(xué)校很重要4.連接副詞when,where,why,how引導(dǎo)的主語從句。這些連接副詞相當(dāng)于副詞，在從句中充當(dāng)狀語。

Whyhedidthisisnotknown.他為什么做這件事還不知道。

Whenhewillcomeisstillunknown.他什么時候來還不知道。

Itisnotknownwhyhedidthis.他為什么做這件事還不知道注意：wh-引導(dǎo)的主語從句也常用it作形式主語。5.也可用whatever,whoever,whomever,whenever,wherever等詞引導(dǎo)主語從句，表示“無論什么”、“無論誰”、“無論何時”、“無論在（到）哪里”等。

Whateverhegaveyoushouldbehandedin.他無論給你什么都要上交

Whoevertoldyouthatwaslying.無論誰告訴你，那都是撒謊

Whoevercomesiswelcome.無論誰來都是歡迎的[參考答案]1-10CBACDDDCAA11-20CBDACBDBAC21-30BABBCBAA主語從句專項練習(xí)1.________makesmistakesmustcorrectthem.A.WhatB.ThatC.WhoeverD.Whatever2.Itworriedherabit____herhairwasturninggrey.A.whileB.thatC.ifD.for3.Whenandwhyhecamehere________yet.A.isnotknownB.arenotknownC.hasnotknownD.havenotknown4.________isnoreasonfordismissingher.A.BecauseshewasafewminuteslateB.OwingtoafewminuteslateC.ThefactthatshewasafewminuteslateD.Beingafewminuteslate5.________Tomlikedtoeatwasdifferentfrom________.A.That…thatyouhadexpectedB.What…thatyouhadexpectedC.That…whatyouhadexpectedD.What…whatyouhadexpected6.________wegoswimmingeveryday________usalotofgood.A.If...doB.That...doC.If...doesD.That...does7.It________Bobdrivesbadly.A.thinksthatB.isthoughtwhatC.thoughtthatD.isthoughtthat8.It'suncertain________theexperimentisworthdoing.A.ifB.thatC.whetherD.how9.________theboydidn'ttakemedicinemadehismotherangry.A.ThatB.WhatC.HowD.Which10.____wecan'tgetseemsbetterthan____wehave.A.What,whatB.What,thatC.That,thatD.That,what11.____youdon'tlikehimisnoneofmybusiness.A.WhatB.WhoC.ThatD.Whether12..____we'llgocampingtomorrowdependsontheweather.A.IfB.WhetherC.ThatD.Where13._________isgoingtodothejobwillbedecidedbythePartycommittee.A.ThatB.WhyC.HowD.Who14._______we'llfinishtranslatingthebookdependsonthetime.A.WhenB.WhyC.WhatD.That15.______hewon'tgothereiscleartoallofus.A.HowB.WhatC.WhyD.This16.______thehousewillbebuiltwillbediscussedattomorrow'smeeting.A.IfB.WhereC.ThatD.What17.._______youcomeornotisuptoyou.A.WhatB.IfC.WhyD.Whether18..Is_______truethatthefamousscientistwillgiveusalecturenextweek.A.thatB.itC.isD.he19.._______teamwillwinthematchisamatterofpublicconcern.A.WhichB.ThatC.IfD.How20..________leavestheroomlastoughttoturnoffthelights.A.AnyoneB.ThepersonC.WhoeverD.Who21.________hereallymeansis________hedisagreeswithus.A.What,whatB.What,thatC.That,thatD.That,what22.Ithasnotbeendecided________theywillleaveforBeijing.A.whenB.thatC.whatD.why23.____hewillgotoworkinamountainvillagesurprisesallofus.A.WhatB.ThatC.WhetherD.If24.____youdon’tlikehimisnoneofmybusiness.A.WhatB.ThatC.WhoD.How25.____alltheinventionshaveincommonis____theyhavesucceeded.A.What;whatB.That;thatC.what;thatD.That;what26.____appearedtomethatheenjoyedthefoodverymuch.A.WhatB.ItC.AllthatD.That27.Itiswidely______thatsmokingcancausecancer.A