必修3unit4-grammar主语从句

Welcome!•Howdinosaursdisappearedisnotonlyaquestionwhichinterestsbiologistsandgeologists.Itisafavoritetopicfordiscussionforphysicistsandastronomers.Theywouldliketoknowwhydinosaursbecameextinctbecausethismayhelpthemfindwaystosolvetheproblemofglobalwarming.Somescientistsbelievethattheearthslowlybecamehotanddrydozensofmillionsofyearsago.Howtheclimatechangedisuncertain,butwaterandfoodsupplydecreasedandsothedinosaursgraduallydiedout.•However,themammalssurvived.Otherscientistsbelievethatcometcrashedintotheearthlongagoandcausedthedisappearance.Asaresultofthisevent,agreatdustcloudformedintheskyblockingoutthesunlight.Withoutsunlight,mostplantssoondiedandsomanydinosaurspeciesbecameextinct.Sincetheiceage,theclimateoftheearthhasnotchangedverymuch.However,whethertheclimatewillchangeagainisaconcernforeverybodyonearth.1.主语从句：从句在句中充当主语成分1)Howdinosaursdisappearedisnotonlyaquestionwhichinterestsbiologistsandgeologists.onlyaquestionwhichinterestsbiologistsandgeologists.2)Howtheclimatechangedisuncertain,butwaterandfoodsupplydecreasedandsothedinosaursgraduallydiedout.3)Whethertheclimatewillchangeagainisconcernforeverybodyonearth.1．引导主语从句的连接词有三类：(1)连词that、whether：whethertheclimatewillchangeagainisaconcernforeverybodyonearth.Whetherhe’llcomehereisn’tclear.Thatpricewillgoupiscertain.Whatshedidisnotyetknown.Whowillwritethepoemhasnotbeendecidedyet.Whateverhedidisright.(2)连接代词who,whom,whose,what,which,whoever,whatever,whichever等3)连接副词where,when,how,why等。Howthishappenedisnotcleartoanyone.Whenhewillbebackdependsontheweather.Howthepyramidswerebuiltisstillamystery.“It’’作形式主语：为了避免主语冗长,句子头重脚轻,经常用it作形式主语,主语从句放在后面作真正的主语.1.Thatweshallbelateiscertain.--It’scertainthatweshallbelate.2.Thattheearthisroundisknowntoall.--3.Thatyoumissedthechanceisapity.--Itisapitythatyoumissedthechance.It’sknowntoallthattheearthisround.4).ThatChinahaswon51goldmedalsinthe29thOlympicsisreported.ItisreportedthatChinahaswon51goldmedalsinthe29thOlympics.注意：1.Whatyouleftareonlyseveraloldbooks.2.Whatyousaidisofgreatimportance.1.“if”不能引导主语从句，应有“whether”引导。3.主语从句的“that”一般不能省。4.“what”引导主语从句时，谓语动词：1）常与其后的名词作表语一致2）根据句子的语境而定。4.主语从句需注意的问题2.主语从句中用陈述语序。Itisdoubtfulifhehasreceivedyourletter.1.Whereshallwespendtheholidayisn’tdecided.2.Youhavemadeamistakeisafact.3.Thatiscertainthatwecanwin.4.Nomatterwholeavestheroomlastoughttoturnoffthelights.5.Ifthepolicemenwillcomeisnotcertain.weshallThatyouhaveItisWhoeverwhether改错练习1.___hemadeanimportantspeechatthemeetingwastrue.A.ThatB.WhyC.WhatD.How2.___we’llgocampingtomorrowdependsontheweather.AIfBWhetherCThatDWhere3.___isknowntousallisthatAmericaisadevelopedcountry____theFirstWorld.a.Which;belongtob.As,belongedtoc.What;belongingtod.It;belongingto4.It’sknowntousall___aformofenergy.A.waterisB.thatwaterisC.iswaterD.thatwaterto5.Itworriedherabit___herhairwasturninggray.A.whetherB.thatC.whatD.when6.WhatIsayandthink___noneofyourbusiness.A.isB.areC.hasDhaveThankyou!