名词性从句之主语从句讲解

名词性从句之主语从句讲解名词性从句之主语从句讲解名词性从句之主语从句讲解资料仅供参考文件编号：2022年4月名词性从句之主语从句讲解版本号：A修改号：1页次：1.0审核：批准:发布日期：名词性从句---主语从句

1.Whatisneededforthespacetripiscarefulpreparation.2.Herwishisthatshecanloseweightsoon.3.Ithinkthatwomancanreacheveryhighachievementsinmanyfieldsofscience.4.Wewereveryexcitedatthenewsthatourteamhadwon.引导名词性从句的关联词可分为三类：一．从属连词：that（无任何词意）whether,if（均表示“是否”表明从句内容的不确定性）asif,asthough（均表示“好像”，“似乎”）以上在从句中均不充当任何成分二．连接代词：what,who,whom,which，whose,whatever,whoever,whichever(作主宾表定)三．连接副词：when,where,how,why(作状语)I.主语从句

1.定义：在句子中担当主语的是一个从句,这个从句就叫做主语从句。

2.位置：主语从句是在复合句中充当主语的从句，通常放在主句谓语动词之前或由形式主语it代替，而本身放在句子末尾。

3.引导主语从句的关联词：

(1)从属连词that,whether,if(在从句中不充当成分，仅起连接作用)

ThatJackwonthematchyesterdaysurprisedus.

Whetherhe’llcomehereisn’tclear.(此处不能用if)

(2)连接代词who,whom,whose,what,which,whoever,whatever,whichever(充当主宾表定)

Whatshedidisnotknown.

Whoevercomesiswelcome.

(3)连接副词where,when,how,why(在从句中充当状语)Howthishappenedisnotcleartoanyone.Whenthemeetingwillbeheldisdecidedbyourmanager.

4.有时为了避免头重脚轻，常用it作形式主语，而把真正主语放在句子末尾。

Howthebookwillselldependsonitsauthor.=Itdependsonitsauthorhowthebookwillsell.

Thatheisthebeststudentintheclassisobvious.=Itisobviousthatheisthebeststudentintheclass.用it作形式主语的几种常见结构：(1)Itis＋名词＋从句

Itisafactthat…事实是…Itisanhonorthat…非常荣幸

Itiscommonknowledgethat…是常识

(2)Itis＋形容词＋从句

Itisnaturalthat…很自然Itisstrangethat…奇怪的是…

(3)Itis＋不及物动词＋从句

Itseemsthat…似乎…Ithappenedthat…碰巧…

Itappearsthat…似乎…

(4)It＋过去分词＋从句

Itisreportedthat…据报道…Ithasbeenprovedthat…已证实…

Itissaidthat…据说…

注意：主语从句不可位于句首的五种情况

(1)if引导的主语从句不可居于复合句句首。(例子见上面)

(2)Itissaid,(reported)…结构中的主语从句不可提前。

例如：ItissaidthatPresidentXiwillvisitourschoolnextweek.

(3)Ithappens…,Itoccurs…结构中的主语从句不可提前。

例如：Itoccurredtohimthathefailedintheexamination.

(4)Itdoesn’tmatterhow/whether…结构中的主语从句不可提前。

例如：Itdoesn’tmatterwhetherheiswrongornot.

(5)含主语从句的复合句是疑问句时，主语从句不可提前。

例如：Isitlikelythatitwillrainintheevening？

5.语序：主语从句用陈述语序。(关联词位于句首不能省略)

Howhebecameagreatscientistisknowntousall.

Whothewatchbelongstoisunknown.

Thathefinishedwritingthecompositioninsuchashorttimesurprisedusall.

6.主语从句中注意的事项：

1）主语从句后的谓语动词一般用单数。

Whateverhesaysisofnoimportance.

Whoeversaysthisiswrong.

但谓语动词用单数还是复数，不可一概而论，而要视句子的意义而定

WhatIneedismoney.

WhatIneedarebooks.

2）what与that在引导主语从句时的区别：

what引导主语从句时在从句中充当句子成分，如主语、宾语、表语，而that则不作任何成分。

Whatyousaidyesterdayisright.

Thatsheisstillaliveisaconsolation.

3）it作形式主语和it用于强调句的比较：

it作形式主语代替主语从句，主要是为了平衡句子结构，主语从句的连接词没有变化；而it用于强调句则是对句子某一部分进行强调，无论强调的是什么成分，都可用连词that。被强调部分指人时也可用who/whom。

①主语从句常用it作形式主语，一般常用句型为：Itis+{名词/形容词/过去分词}+主语从句例如：

Itisstillaquestionwhethershewillcomeornot.

Itisstrangethatyoushouldlikehim.

Itisstillunknownwhichteamwillwinthematch.

②而强调句则不同，它的结构是：It+be+被强调部分+that+从句

强调主语：Itisthetimesthatproducetheirheroes.时势造英雄

强调宾语：ItisEnglishthatteachesus.

强调状语：ItwasinshanghaithatIsawthefilm.

判断是否是强调句有一个方法，就是将that以后的“句子的其余部分”拿出来单独看，看有没有缺成分，缺的是什么成分，再把谓语动词后面that前面的那部分，带到你认为缺成分的地方，如果放进去是一句完整的句子了，那就说明是强调句。

Itisstillamysterywhatcausedtheaccident.

Itisamysterythathisdeathremained.

4）whether与if

whether引导主语从句时,常置于句首(此时whether不能用if代替),也有后移的用法(此时whether可以用if代替)

Whethertheywillcomeisnotyetknown.

Itisnotyetknownwhether/iftheywillgothere.

whether和if的区别还有：

1.引导表语从句用whether

Thequestioniswhetheryoushouldacceptit.

2.whether可以引导从句作介词的宾语

I’mnotinterestedinwhetherthey’llgoornot.

Itdependsonwhetherwehavegotenoughmoney.

3.whether可以直接跟动词不定式连用

Ididn’tknowwhethertolaughortocry.

Shehasn’tdecidedwhethertogoornot.4.与ornot连用时，只能用whether。Idon'tknowwhetherIshouldgothereornot.随堂练习：1.hashelpedtosavethedrowninggirlisworthpraising.A.WhoB.TheoneC.AnyoneD.Whoever2.Itwashesaiddisappointedme.A.what;thatB.that;thatC.what;whatD.that;what3.we’llgocampingtomorrowdependsontheweather.A.IfB.WhetherC.ThatD.Where4.hesaidatthemeetingsurprisedeverybodypresent.A.WhatB.ThatC.whichD.who5.wastoreturntoschool.A.ThatreallyinterestedhimB.WhatreallyinterestedhimC.WhichreallyinterestedhimD.Thatinteresthimreallyhemadeanimportantspeechatthemeetingwastrue.A.ThatB.WhyC.WhatD.How7.Itworriedherabit______herhairwasturninggray.A.whetherB.thatC.whatD.whenIsayandthink___noneofyourbusiness.A.isB.areC.hasDhave9.Does_______matterifhecan'tfinishthejobontimeA.thisB.thatC.heD.it10._______isafactthatEnglishisbeingacceptedasaninternationallanguage.A.ThereB.ThisC.ThatD.It11._______whattheytoldmereallytrueA.HasB.IsC.DoesD.Have12.Itmatterslittle_____amandies,but____mattersmuchis____helives.A.how;what;howB.how;it;howC.why;it;whyD.that;what;that13.____shecouldn'tunderstandwas____fewerandfewerstudentsshowedinterestinherlessons.A.What;whyB.That;whatC.What;becauseD.Why;that14._____