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高中英语语法讲解：名词性从句一、概念名词性从句在句子中起名词作用，它在整个句子中能担任主语、宾语、表语或同位语。根据它在句中充当的不同成分，名词性从句可分别称为主语从句、宾语从句、表语从句或同位语从句。没有主语从句、宾语从句/表语从句，整个句子就缺少了主语/宾语/表语，句子结构不完整；没有同位语从句，句子结构完整，但句意不完整。注：区别于定语从句（形容词性从句）：限制性定语从句相当于一个形容词，修饰主句中的某个名词，做它的定语；非限制性定语从句，几乎完全独立于主句，没有定从，虽然句意不一定完整，但句子结构仍然完整。Iknowthegirlwhoisreadingoverthere.Hecamehomesafeandsound,whichwasagreatrelieftohisfamily.二、4类连接词&注意点1．that（1）连接主句与从句（2）无意义（3）不做从句中的成分（4）能否省略2．if/whether（1）连接（2）表“是否”（3）不做成分（4）whether与if区别3．疑问代词what,who,whom,which&whatever,whoever,whomever,whichever（1）连接（2）表不同含义（3）做从句中的重要成分4．疑问副词when,where,why,how（1）连接（2）表不同含义（3）做从句中的状语三、四种名词性从句1．主语从句（1）普通主语从句Thatheisstillaliveissheerluck.注：that位于句首引导主从，一定不省。Whethertheplanispracticableremainstobeseen.Whatweneedaremanyinstructivebooks.Whatweneedismoretimeandmoney.注：主从做主语，主句谓语动词一般用单数，但what引导的主从，根据后面表语的意义一致原则。Whenandwherethemeetingwillbeheldisnotclear.WhenTomwillcomeandwhatLucywillsayarenotclear.注：一套主谓结构谓语动词用单数，两套则用复数。Whichteamwillwinishardtopredict.Howhemadesuchalargefortuneisstillamystery.（2）用it做形式主语为（避免头重脚轻）的主语从句，常见句型有：Itisapity/ashame/nowonder/apleasure/anhonor/afact/commonsense/nthat…Itishigh/abouttimethat…Itisthefirst/second/...timethat…Itisobvious/strange/necessary/vital/essential/natural/notuncommon/likely/adjthat...Itissaid/reported/announced/believed/estimatedexpected/recommended/ppthat…Ithappensthat…；Itturnedoutthat…Itoccurto/dawnon/hit/strikesbthat…Itdoesn’tmatterthat/whether/how…注：连接代词一般不用it做形式主语，e.g.Whathesaidinterestedmegreatly.2．宾语从句：（1）做及物动词的宾语Idon’tknowwhathisnameis.（2）做介词的宾语MyteacherwassatisfiedwithwhatIdid.Thefilmremindedmeofhowmygrandmabroughtmeup.AtwhatIthinkistheappropriatetime,Iwilltellyouallthetruth.注：介词后面的宾从一般不用that引导，但inthat和exceptthat是例外Hedifferedfromhisclassmatesinthathedevotedallhissparetimetoreading.IknownexttonothingaboutTomexceptthathecomesfromtheUS.（3）放表语形容词后的宾语从句Iamgladthatyoumakeittomyparty.Sheisnotsurewhatwillhappennext.（4）it做形式宾语YoumaydependonitthatIwillalwayscometoyouraid.（介词后宾从）Iwillseetoitthateverythinggoessmoothly.Ioncetookitforgrantedthatmyparentsputmyneedsfirst.（动词+宾语+宾补结构）IwanttomakeitclearthatIwillneveracceptyourmoney.Theythink/consideritimpossiblethathousepriceswilleverdrop.Ilike/hateitwhen…；Iwouldappreciateitif…（句型）注1：一个动词或介词后接一个以上宾从时，第一个宾从的that可省，第二个开始的that不可省Iforgot(that)myresearchpaperwasdueonTuesdayandthatIhadleftitunfinishedsincelastFriday.注2：宾从时态一般与主句时态呼应，客观真理自然现象除外。Inthemiddleage,peopledidn’tbelievethattheearthmovesaroundthesun.注3：否定前移Idon’tthinkheisfitforthejob,ishe?3．表语从句：（1）be+表从Theproblemisthathehasneverbeentoanothercountryalone.表从中that一般不省。Myquestionwaswhysheturnedmyinvitationdown.（2）句型：looks/seems/appears+asif/though…,“看起来似乎好像”Helooksasifhekneweverything.(与事实相反，虚拟)Itseemsasifourteamisgoingtowin.(与事实相符，真实)（3）句型：that/thisiswhy/because…,“这是因为/…的原因”Hewaslateforschoolyesterday.Thatwasbecausehewasill.Hewasill.Thatwaswhyhewaslateforschool.4．同位语从句解释说明“某些抽象名词”的具体内容：news,word(单数:消息),belief,idea(主意),thought(想法),fact,truth,plan,notice(通知),promise等比较特殊的有：doubt（有/无关于…的疑问）,possibility/chance（有/无…的可能性）,evidence（证据表明）。Iagreewithyourplanthatwesetouttomorrowmorning.Wordcamethathesurvivedthewar.ThereisnoevidencethatlivesexistonMars.注：“无疑问/很确定”连接词用that；“有疑问/不确定”用whetherIhavenodoubtthat…同位从；Thereissomedoubtwhether…同位从=Itiscertainthat…主从；Itisuncertainwhether…主从四、细节考点1.从句语序：（1）陈述句语序，Idon’tknowwhatyourplanis.特例：Herefusestotellmewhatisthematter.（2）主句是疑问句用疑问语序，从句仍用陈述句语序Whatdoyouthinkheisdoing?Whatyouthinkheisdoing?(X)Whatdoyouthinkishedoing?(X)（3）名从中套强调句的情况下的疑问词放在最前面Idon’tknowwhatitwasthatmadehimangry.Idon’tknowitwaswhatthatmadehimangry.(X)2.连接词that的省略总结：（1）只有“vt+宾从”中引导第一个从句的that可以省略；（2）其他“一般不省”（如表从、it做形式主语的主从）；（3）或者“一定不能省”（放句首的主从、同位从、介词宾从、动词宾从的第二三四…个从句中）3.连接词whether/if的区别：a.只有三种情况whether/if都可以：（1）动词后的宾从中（vt除去discuss，decide,depend）Idon’tknowwhether/ifhewillcometonight.（2）it做形式主语的主从中Ithasn’tbeendecidedwhether/ifweshallattendthemeeting.（3）whether/if…ornot分开时Idon’tknowwhether/ifhewillcomeornottonightb.其他情况只用whether不用if：（1）放句首的主从Whetherweshallattendthemeetinghasn’tbeendecided.（2）介词后的宾从Iamskepticalaboutwhetherhewilltellthetruth.（3）表从Thequestioniswhetherthefilmisworthseeing.（4）同位从Idarenotaskthequestionwhethershelikesmeornot.（5）whetherornot紧密相连时Idon’tknowwhetherornothewillcometonight.（6）whether+todo不定式Weareuncertainwhethertoleaveheretomorrow.4.表示“建议，命令，要求”的词（如suggest/suggestion,propose/proposal,recommend/recommendation,require/requirement,order,demand等）构成的宾从、表从、同位从中用should虚拟语气，should可省略，表示“某人应该做某事”之意Isuggestthatyoushouldadoptthenewteachingmethod.Mysuggestionisthatyoushouldadoptthenewteachingmethod.Doyouagreewithmysuggestionthatthenewteachingmethodshouldbeadopted?5.who,whom和whoever,whomever的区别who是“谁”的意思，表疑问；whoever表无论谁、任何…的人”，相当于anyonewho，无疑问意味。Canyoutellmewhothatgentlemanis?Whoeverleavestheroomlastoughttoturnoffthelights.“无论谁最后离开房间”或“任何最后离开房间的人”Haveyoudecidedwhomyouaretonominateasyourcandidate?Youcangivethetickettowhomeveryoulike.你可以把票给任何你想给的人。Themanagerhasdecidedtoput_________hethinksisenergeticandcleverinthepositionoftheleadershipofthecompany.6.which+n与what+n的区别：WhicheverteamwinsonSaturdaywillg