Unit4AstronomythescienceofthestarsGrammarWord主语从句【语境展示】观察下面句子，并试着归纳主语从句的用法要点。1.Thathehadfinishedwritingthecompositioninsuchashorttimesurprisedusall.2.Whethertheplanistobecarriedoutstillneedstobediscussed.3.Whowillgototheenergyconferenceisnotimportant.4.WhatIwantedwasafewdays’rest.5.Whichhotelheisstayingatisunknowntous.6.Whenthesportsmeetingwillbeheldhasnotbeendecidedyet.7.Whereweshouldleavethegarbageisaproblem.8.Whyheisn’theretodayisamystery.9.Howthemandiedpuzzledusall.【自我归纳】在复合句中，担任主语的从句叫主语从句（句1—句9）。引导主语从句的词有：连词that,whether（句1、句2）；连接代词who,what,which（句3—句5）；连接副词when,where,why,how（句6—句9）等。一、由连词that,whether引导的主语从句1.that引导主语从句时，无实际意义，只起连接作用，不充当任何句子成分，当它引导的主语从句置于句首时，that不能省略（句1）。2.whether意为“________”，不可以省略（句2）。二、由连接代词who,what,which引导的主语从句连接代词who，what，which引导主语从句时，在从句中充当主语、宾语或________等（句3—句5）。三、由连接副词when,where,why,how引导的主语从句连接副词when,where,why,how引导主语从句时，在从句中充当状语（句6—句9）。【拓展】当主语较长时，常用it作形式主语，而将主语从句放在句末。如：Itisknowntoallthatlighttravelsinstraightlines.Itwasclearenoughwhathemeant.Ithasnotbeenannouncedwhentheplaneistotakeoff.常见的由it作形式主语的句型如下：①It+be+名词+从句。常用此句型的名词有：fact,rule,pleasure,truth,pity,mystery等。如：ItisafactthatEnglishisbeingacceptedasaninternationallanguage.Itisapitythatyoucan’tswim.Itwasamysteryhowthethiefgotin.②It+be+形容词+从句。常用于此句型的形容词有：true,important,strange,necessary,clear,certain等。如：Itistruethattheearthisround.Itisstrangethatheknowsnothingaboutit.Itwasnotcleartomewhyhebehavedlikethat.③It+动词+从句。常用于此句型的动词有：seem,appear,happen,follow等。如：Itseemsthatyou’reright.IthappenedthatMarywasn’tathomethatday.④It+be+过去分词+从句。常用于此句型的过去分词有：known,said,proved,reported,suggested等。如：Isitknownwherehewent?It’ssaidthathewasaspyduringthewar.注意：1.that引导的主语从句置于句首时，that不能省略。但是如果用it作形式主语，而把主语从句放在句末时，that可以省略。如：Thatyourpicturesshouldsurprisethemwasquitenatural.Itwasnatural(that)yourpicturesshouldsurprisethem.2.如果主语从句置于句首，则不能用if引导，而用whether；但如果用it作形式主语，而把主语从句放在句末时，也可以用if引导。如：WhetherTomreallysawSharonwasdoubtful.Itwasdoubtfulwhether/ifTomreallysawSharon.【即学即练】I.用适当的连接词完成下列句子。1.________wewillgotovisitHongKonginthiswintervacationremainsunknown.2.________willtaketheplaceofMr.Liasournewheadmasterhasn’tbeendecided.3.________causedtheaccidenthasn’tbeenmadeclearyet.4.It’sapity________Bobcan’ttakepartintheoutingwithusbecausehismotherisill.5.Itdoesn’tmatter________MaryhasbeentoAmericaornot.________reallymattersisthatshecanspeakEnglishfluently.6.Ithasbecomewidelyaccepted________oneglassofredwineperdayisgoodforyourheart.7.________gunpowderwasfirstinventedbytheChineseisknowntousall.8.________seemseasytosomepeopleseemsdifficulttoothers.II.用适当的连接词补全下面的对话。Lucy:Whyareyoulookingsohappy?Jenny:I’vejustattendedalecture.1.________thespeakersaidmademeexcited.Lucy:Whatwasitabout?Jenny:Abouthealth.Itseems2.________alotofpeopledon’tknowhowtokeephealthy.Lucy:Soundsgreat.3.________I’mc...
