英语语法：高中英语It的用法

英语语法：高中英语It的用法一、It用作实词表达以下概念:指代前文提到的事物，如前文中的this,that；替代前文中的内容；指代一位性别不明的小孩或未知的人；指代未指明但谈话双方都知道的那件事；指代时间、天气、气候、距离等自然现象……二、It用作形式主语替代作主语的从句、动词不定式、动名词，而把真正作主语的从句、动词不定式、动名词置于句尾。It作形式主语的常见句型：代作主语的动词不定式，其句型为:Itbeadj.(forsb.)todosth.此处adj.通常为描述事件的形容词：easy,difficult,hard,necessary,unnecessary,possible,impossible,likely,unlikely,right,wrong,important,unimportant,legal,illegal,well-mannered,ill-mannered,polite,impolite,clear,obvious,certain,suitable,proper,fit,useful,useless,dangerous…例:Itisillegal(forateenager)todriveacarwithoutalicense.Itbeadj.ofsb.todosth.此处adj.通常为描述人的形容词：kind,unkind,nice,rude,cruel,considerate,thoughtful,thoughtless,careful,careless,silly,foolish,stupid,clever,wise,crazy.例:It'skindofyoutohelpmewiththeproblem.It替代作主语的动名词的常见句型：It'snogood/usedoing…It's(well)worthdoing…It'ssurprisingthatIt'ssurprisingthat…(should)竟然It's(well)worthone'swhiledoing/todo…It's(well)worthwhiledoing/todo例：It'snousecryingoverspiltmilk(覆水难收).It替代作主语的从句常见句型：Itis+noun+从句例：Itisnosecretthatthepresidentwantstohaveasecondtermatoffice.Itisadj.+clauseIt'sapity/shamethat•••(should)It'sapity/shamethat•••(should)竟然例:It'simportantthatyoushouldapologizetoherforyourrudeness.(=It'sofmuchimportancethatyoushouldapologizetoherforyourrudeness.)Itverbsb.+clause=Itisv-ing+clauseIt+surprise/delight/interest/disappoint/worry/disturb/annoy/amaze/bother/concern/frighten/please/angersb.that…例:Itworriedmethatshedrovesofast.(=Itwasworryingthatshedrovesofast.)Itverb(tosb.)that…二sb/sthverbtodo例:It(so)happened/chancedthattheywereout.(=Theyhappened/chancedtobeout.)Itisv-edthat・••二sb/sthistodo(verb=say,report,think,believe,hope,expect,agree,accept,decide,determine,intend,plan,understand,know)例:Itissaidthatthecouplehavegottendivorced.(=Thecouplearesaidtohavegottendivorced.)Itisv-edthat…(should)…(verb=demand,request,require,order,suggest,advise,recommend例Itissuggestedthattheyshouldbeginwiththethirdquestion.三、It作主语的句型1.Ittakessb.…todo…(二sbtakes…todo…)某人用多长时间做某事例:Ittookthemenaweektomendourroof.(=Thementookaweektomendourroof.)2.It's(just)(un)likesb.todo…(不)像某人做某事的风格例:Itwas(just)likehimtothinkofhelpingus.It's(about/high)timethat…should/v-ed…是该做某事的时候了例:It's(about/high)timethatweshouldtakeaction.It'sthex-thtime(that)…havev-ed…第几次做某事了例:It'sthethirdtimethathehasfailedthedrivingtest.Itis/hasbeen…since*^continuousv-ed（延续性动词）某动作持续了多长时间例:It's10yearssincehelivedhereItwas（not）…before…过（不）了多长时间某动作发生了例:Itwasnotlongbeforetheyarrived.

四、It作形式宾语用来替代作宾语的从句、动词不定式、动名词，而把真正作宾语的从句、动词不定式、动名词置于句尾。It作形式宾语的常见句型：suppose,consider,feel,make,keep•…)1.verb+it+adj./noun(for/of)todo/clause(verb=think,believe,1.verb+it+adj./noun(for/of)todo/clause(verb=think,believe,例:Ithinkithardforyoutodothetaskonyourown./Ithinkithardthatyou'lldothetaskonyourown.2.verb+it+adj./noun(one's)doing(adj.=useless/worth/worthwhile)(noun=nouse/nogood/worthone'swhile/awasteoftime/money/energy/words)(verb=think,believe,suppose,consider,feel,make,keep•…)例:I'llmakeitworthyourwhiletellingmeabouthissecret.3.verb+it+3.important/unimportant/necessary/unnecessary/natural/essentialthat…(should)…verb+it+ofmuch/great/no/littleimportancethat…・(should)…(verb二think,believe,suppose,consider,feel,make,keep•…)例:Ithinkitimportantthatyou(should)attendtheconference.verb+it+as+noun/adj.+clause(verb=accept,regard,take,see,view)例:Thelecturertakesitasencouragingwhensomanystudentsattendhislecture.v.+it+prep.+that…oweittosb.that…把…归功于…leaveittosbthat…把…留给某人去做takeitforgrantedthat…想当然keepitinmindthat…例:Don'tbothertoarrangeanything.Justleaveittometosortout.It用在不能直接跟宾语从句的动词后面，尤其是表示好恶的动词后，enjoy,like,love,dislike,r