实用文案标准文档常用it作形式主语的句型结构◇It+be+形容词+that-从句可用于此句型的形容词有:wonderful,true,good,right,wrong,(un)important,useless,surprising,clear,unusual,lucky,certain,necessary等。如:①Itisquitecertainthathewillbeatthemeeting.②Itissurprisingthathecamelatetoschoolthismorning.③Itisimportantthatwe(should)studyhard注意:该句型中的形容词是(un)important,necessary等时,从句应为(should)+动词原形。◇It+be+-ed分词+that-从句适用该句型的过去分词主要有:said,reported,announced,hoped,thought,told,believed,expected,decided,suggested,known等。如:①Itishopedthatonedaytheywillhaveenoughanimalstosetthemfree②Itiswellknownthattheearthgoesaroundthesun.③Itissuggestedthatthesportsmeeting(should)beputoffuntilnextweek.注意:该句型的过去分词是suggested时,从句应为(should)+动词原形。◇It+be+名词+that-从句适用该句型的名词(词组)有:apity,anhonor,agoodthing,afact,asurprise,goodnews,one’sduty等。如:①Itisapity(that)youmissedthesportsmeetinglastweek.②ItisafactthatEnglishisbeingacceptedasaninternationallanguage.◇It+seem/appear/happen的适当形式+that从句。该句型常可以转换成含不定式的简单句。如:①Itseemsthatthereisabigwastepipecomingdownfromthetown.→Thereseemstobeabigwastepipecomingdownfromthetown.②Heappearedtobecalm,butinsidehisheartwasbeatingwildlywithfear.→Itappearedthathewascalm,butinsidehisheartwasbeatingwildlywithfear.◇Itdoesn'tmatter(It’snowonder;Itdoesn’tmakemuchdifference等)+when/where/which/whether等从句。如:①Doesitmatterifhecan'tfinishthejobontime?②Theyareallclassmates.Itisnowonder实用文案标准文档theyshouldhelpeachotherwiththeirstudies.◇It+be+adj./n.(forsb./ofsb.)+todosth.该句型中的形容词通常是表示事物的特点或特征的如difficult,hard,easy,impossible,necessary,important等,此时用for;或表示人的性格特征或特点的如nice,good,bad,kind,silly,foolish,wise,clever,careless,rude,brave,cruel,careful,grateful等,这时要用of。如:①Itisfoolishofyoutogiveupsuchagoodchance.②ItisnecessaryforcollegestudentstomasteratleastaforeignlanguageIt作形式主语常见句型动词不定式,动名词或主语从句作主语时,通常把它们放在谓语动词前,而用it作形式主语,放到句首,常见句型有:1.It+be+形容词+主语从句,如:ItisuncertainwhetherhecancometoJenny’sbirthdaypartyornot.2.It+be+名词词组+主语从句,这类名词有:afact,apity,ashame,anhonour,aquestion等,如:It’sapitythatyoumissedtheexcitingfootballmatch.Itremainsaquestionwhetherhewillcomeornot.3.It+be+过去分词+主语从句,这类过去分词有:announced,believed,expected,hoped,decided,reported,said,shown等,如:Itisreportedthat16peoplewerekilledintheearthquake.Itisnotdecidedwhowillgivetheoperationtothepatient.4.It+不及物动词(seem,appear,happen等)+主语从句,这类不及物动词有:appear,happen,seem等,如:Itseemedthathedidn’ttellthetruth.实用文案标准文档IthappenedthatIwasoutwhenhecalled.5.It+be+形容词+forsb.)+动词不定式这类句型常用形容词easy,difficult,hard,important,possible,wise等作表语,有时候为了强调不定式动作的执行者,常在不定式前加forsb,如:It’snecessaryfortheyoungtomastertwoforeignlanguage.Itisunwisetogivethechildrenwhatevertheywant.这类形容词有:easy,difficult,hard,important,possible,wise6.It+be+形容词+ofsb.+动词不定式,这类形容词常是表示心理品质,性格特征的形容词,如:kind,nicestupid,clever,foolish,polite,impolite,silly,selfish,considerate等。某人和这些形容词可以构成主系表结构。如:It’sverykindofyoutohelpmewiththework.=Youarekindtohelpme.Itseemedselfishofhimnottosharehisdictionarywithothers.=Heseemedselfishnottosharehisdictionarywithothers.7.It+be+名词词组+动词不定式,如:Itisnotagoodhabittostayuptoolate.8.It+be+名词或形容词+动名词,这类名词和形容词常常是:good,nogood,nouse,awasteof,useless,senseless等,如:It’sawasteoftimetalkingtoheranymore.Itisnousearguingaboutthematterwithhim.9.It+take(sb.)+时间(金钱)+动词不定式,如:Ittooktheworkersalmostthreeyearstofinishbuildingthedam.Itwilltakeawholedaytogettothetopofthemountainonfoot.实战演练:实用文案标准文档1.Itisgenerallyconsideredunwisetogiveachildheorshewants.(NMET1997)A.howeverB.whateverC.whicheverD.whenever2.Infactisahardjobforthepolicetokeeporderinanimportantfootballmatch.(2001上海)A.thisB.thatC.thereD.it3.isafactthatEnglishisbeingacceptedasaninternationallanguage.(NMET1995)A.ThereB.ThisC.ThatD.It4.Isnecessarytotakeoffourshoeswhenweenterthelab?(MET88)A.everyoneB.thisC.herD.it5.________willtakeyoualotoftimetofindhiminthecrowd.A.ItB.IC.WeD.They6.Itisnousehis_________there,thesituationishopelessnow.A.togoB.tobegoingC.goingD.havinggone7.Itisnevertoolatetolearn,________?A.isitB.isn’titC.doesitD.doesn’tit8.___________isknowntoallthatShenzhouVILaunchedSuccessfully.A.AsB.WhatC.ItD.That9._______isreportedinthenewspaper,theEarthquakeineastChina'sJiangxiProvincekilled13people实用文案标准文档A.ItB.AsC.ThatD.What10.___________certainthathisinventionwillmakepeople’slifeconvenient.A.That’sB.ThisisC.It’sD.What’s11._________thatthereisanotherfootballmatchontheairthisevening.A.ItsaysB.ItwassaidC.ItissaidD.Whatwassaid12.__________thattheirdaughtergotanopportunitytostudyabroad.A.It’saexcitingnewsB.ThisisanexcitingnewsC.ThisisexitingnewsD.It’sexcitingnews参考答案:1——5BDDDA6——10CACAC11——12CD一、主语从句的概念与类型主语从句在复合句中作主句的主语,引导主语从句的词有从属连词that,whether以及连接代词who,what,which,whoever,whatever,whichever和连接副词when,where,why,how等.例如:Thatshewaschosenmadeusveryhappy.她当选了使我们很高兴.Whatcausedtheaccidentisacompletemystery.是什么导致了这次事故还完全是一个谜.Whethershewillcomeornotisstillaquestion.她是否来还是一个问题.Whichteamwillwinthematchisstillunknown.哪个队会赢得这场比赛还不知道.Whoevercomestothepartywillreceiveapresent.参加聚会的每一个人都将收到一份礼物.Whentheywillstarthasnotbeendecidedyet.他们何时出发还没决定.实用文案标准文档注意:上述例句中的主语从句都是放在句首,但有时为了使句子结构平衡,避免头重脚轻,常用it作形式主语,而把从句放在后面.例如:Itisapitythatshehasmadesuchamistake.她犯了这样一个错误,真是遗憾.