It作形式主语讲解.doc

,It做形式主语主讲人：欧云塔娜,Itsnecessaryfortheyoungtomastertwoforeignlanguage.,Itsawasteoftimetalkingtoheranymore.,Itsapitythatyoumissedtheexcitingfootballmatch.,动词不定式,动名词,从句,形式主语,什么是形式主语？,形式主语是指不定式（短语）、动名词（短语）或从句在某个句子中做主语时，通常把它们放在谓语动词前，it作形式主语代替不定式、动名词、从句，置于句首，而将真正的主语放在句尾。此时为保持句子结构前后平衡，避免头重脚轻，it只起先行引导作用，本身无词义。,Itiseasytobecomeaddictedtosmoking.itisnogoodcryingoverspiltmilk.(覆水难收)ItisamazingthatatmyageIamstillfit.,It作形式主语代替不定式、动词-ing短语或从句,adjp.pn,+,(for/ofsb)todosthdoingsth主语从句,Itbe+,1、It+be+形容词+（forsb.）不定式短语,、it代替不定式短语例1：Itiswrongtotellalie.It为totellalie的形式主语例2：Itisdifficulttoclimbamountain.It为toclimbamountain的形式主语例3：Itisagoodhabittodomorningexercises.It为todomorningexercises的形式主语,1、It+be+adj+(forsb./ofsb./名词词组)+todosth.,a:It+be+adj+forsbtodosth该句型中的adj通常是表示事物的特点或特征的，如difficult，hard，easy，impossible，necessary，important等时，用for；意为做某事时是.eg:Itisnecessaryforcollegestudentstomasteratleastaforeignlanguage.,b、It+be+adj+ofsbtodosth该句型中的adj通常用来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等时，要用of。意为某人做某事,某人是.eg:Itisfoolishofyoutogiveupsuchagoodchance.,c:It+be+名词词组+动词不定式eg.Itisnotagoodhabittostayuptoolate.常见句型：Ittakes/tooksb.sometime/moneytodosth.,2、It+be+动名词短语,it代替动名词ing形式常见句型：Itisnogood（use）doingsth.例1：Itisnouselearningwithoutthinking学而不思则罔=Thereisnouse(in)learningwithoutthinking.真正的主语为learningwithoutthinking.例2：Itisnogoodcryingoverspiltmilk.真正的主语为cryingoverspiltmilk.,3、It+be+that从句,it代替that从句a:It+be+adj.+that从句（这是that从句中最常用的一种）如若形容词为important/necessary，good/wrong.表达一种要求，命令或者责备时，多使用虚拟语气（should+V).,1、Itistime+thatsb.+v-ed/shoulddo1、Itistime+thatsb.+v-ed/shoulddoeg.Itstimethatyouwenttobed=Itstimethatyoushouldgotobed.2、Itsnecessary/impossible/important/naturalthatsb.(should)doeg.Itsimportantthatwe(should)keepthebalanceofnature.,2.It+be+V-ed(过去分词)+that从句,这类过去分词有：said,believed,expected,hoped,decided,reported等,如：Itissaidthat据说Itisreportedthat据报道Itissupposedthat据推测Itishopedthat希望Itiswellknownthat众所周知Itisgenerallyconsideredthat普遍认为Itissuggestedthat有人建议,eg:1、Itisreportedthat16peoplewerekilledintheearthquake.2、ItissaidthathehascometoBeijing.,注意：如果主句中的过去分词是表示请求，建议，命令等词如：suggested/ordered/demanded.等时that后的从句要用虚拟语（should+动词原形），should可以省；常译为，“据建议；有命令）Itissuggestedthatthemeeting(should)beputoff.Itwasorderedthatwe(should)arrivethereintwohours.,3.It+be+名词词组+that从句这类名词有：afact,apity,ashame,anhonour，aquestion等，如：eg:1、Itscommonknowledgethatpeoplecanntlivewithoutwater.2、Itsapitythatyoumissedtheexcitingfootballmatch.注意：如若表示出乎意料之意时,从句一般用虚拟语气常译为“竟然”。没有这种意义时，则不用虚拟语气。eg:Itisapitythatsuchagoodthing(should)happeninyourclass.,4、It+不及物动词+主语从句这类不及物动词有：appear/seem/happen等译为“好像./碰巧/如：Itseemedthathedidnttellthetruth.IthappenedthatIwasoutwhenhecalled.,练习题：,把下列句子转换为it做形式主语的句子1.Hewasrudetosayso.(Itwasrudeofhimtosayso.)2.Tryingagainisofuse.(Iti