高中英语必修3-unit4-Grammarppt课件.ppt

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1、Unit4DiscoveringusefulstructuresNounclausesasthesubject4.Tofindyourwaycanbeaproblem.Whatdoestheunderlinedpartserveasineachsentence?3.Smokingisbadforyou.2.Youareastudent.5.“Howdoyoudo?”isagreeting.6.Itiscertainthatweshallbelate.subject1.Beijingisourcapital.Readthesentencesfromthetextandpaya

2、ttentiontotheunderlinedparts.1.Whatitwastobecomewasuncertainuntilbetween4.5and3.8billionyearsago…2.…itwasnotclearwhethertheshapewouldlastornot.3.Whatisevenmoreimportantisthatastheearthcooleddown,waterbegantoappearonitssurface.4.Whatmanyscientistsbelieveisthatthecontinuedpresence…5.Whytheys

3、uddenlydisappearedstillremainsamystery.主语从句是在复合句中充当主语的从句，其功同名词一样。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.Thatheisthebeststudentintheclassisobvious.=Itisobviousthatheisthebeststudentintheclass.主语从句引导主语从句的关联词有三类：(1)从属连词thatThattheyweretruesisterswasclearfromthefa

4、cialresemblancebetweenthem.(2)从属连词whetherWhetherhe’llcomehereisn’tclear.(3)连接代词who,whom,whose,what,which,whoever,whatever,whichever连接副词where,when,how,whyWhatshedidisnotyetknown.Howthishappenedisnotcleartoanyone.Whoevercomesiswelcome.Thathefinishedwritingthecompositioninsuchashorttimesurpri

5、sedusall.Howhebecameagreatscientistisknowntousall.Whothewatchbelongstoisunknown.主语从句用陈述语序关联词位于句首,不能省略1.在主语从句中，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

6、、表语，而that则不然。Whatyousaidyesterdayisright.Thatsheisstillaliveisaconsolation.3.It作形式主语和it引导强调句的比较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引导的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。被强调部分指人是也可用who/whom。Itisstillamysterywhatcausedtheaccident.Itisamysterythathisdeathremained.whether引导主语从句时，常置于句首

7、（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.4.whether与ifwhether和if的区别还有：1.引导表语从句用whetherThequestioniswhetheryoushouldacceptit.2.whether可以引导从句作介词的宾语I’mnotinterestedinwhetherthey’llgoornot