英语中it用法

it用法it用作主语it指代事物、动物、婴儿或未知的人Whatisthis?--Itisabook.Someoneisatthedoor.--Whoisit?Hernewbabyistiny.Itonlyweighs2kilos.•指代天气、时间、距离、季节、事物的状态和自然环境等•Itisgettingcolderandcolder.•ItistwoyearssinceIlastsawyou.•Itwasveryquietinthecafe.•HowisitwithMr.Rose?•Itisonlytwentyminutes'drivetoourcollege.•it作形式主语，代替不定式、动名词或从句，使原来的这些主语可以放在句子后面，避免句子头重脚轻。•1.it代替不定式作主语•Itcostme$25tobuythedictionary.•IsitnecessarytocompletethedesignbeforeNationalDay?•It'sagoodideatohavealittlenotebookhandby.•注意：有时不定式前面有一个for引起的短语，表示不定式逻辑上的主语，用it作形式主语时，构成下面句型•Itis+adj.+forsb.+todo•此句型中的形容词为静态形容词，即描写人或物的静态特征的形容词，用来表示客观情况。这样形容词有：•easy,difficult,important,hard,necessary,essencial,•impossible,dangerous,common,unusual,big,•small,tall,long,short,wide,old,young,beautiful等•ItisverydifficutformetolearnSpanish.•Itisgettinghardereverydayforapoormantogetaliving.•注意：有时不定式前面有一个of引起的短语，表示不定式逻辑上的主语，用it作形式主语时，构成下面句型：Itis+adj.+ofsb.+todo•此句型中的形容词为动态形容词，即指那些有动作含义的词，或为描写人或物的特征或品质的形容词，这样的形容词有：•bold,brave,busy,careful,careless,clever,considerate,cruel,foolish,friendly,generous,good,honest,kind,lazy,nice,noisy,polite,rude,reasonable,selfish,shy,silly,stupid,thoughtful,wicked等•Itwasgenerousofyoutocontributesomuch.•Itwascarelessofhertoloseherkeyofthesafe.•2.it代替动名词作形式主语，而作主语的动名词常放在表语后，在此句型中的表语有下列名词和形容词：•nogood,nouse,awasteoftime,fun,hardwork,pity,awonder,dangerous,difficult,•senseless,useless,foolish,nice,hard,•interesting,worth,worthwhile,terrible,tiring,•funny•It’snousestudyingforanexamatthelastminute.•Itisdifficultfindingyourwayaroundhere.•3.it代替从句作主语，有以下四个常见句型•1)It+be+adj.+that从句•这样的adj通常有：•possible/probable/likely很可能•impossible/unlikely不可能•obvious显而易见•certain很肯定•plain很明显true真的•clear很清楚fortunate幸运的是•Itwasquiteplainthatshedidn'twanttocome.•Howisitpossiblethatamancanfallsolow?•注意：当形容词为下列形容词时，从句可用虚拟语气,为（should+）动词原形•advisable适当的，合理地better较好的•preferable优越的，较好的essential必要的•important重要的insistent坚持的•natural自然的necessary必要的•desirable理想的urgent紧迫的•unfair不公平的•Itisunfairthatsomanypeopleshouldlosetheirjobs.•Itisessentialthatyou(should)winthevoters'hearts.•Itisimportantthatthismissionnotfail.•2)it+be+n.+that从句•commonknowledge常识•anhonour非常荣幸ashame可耻•awonder是个奇迹nowonder不足为奇•afact事实goodnews好消息•apity遗憾aquestion问题•Itisawonderthatheisstillailve.•Itisstillaquestionwhenweshallhaveoursportsmeet.•注意：在此句型中，如果表示惊讶、遗憾等感情，that引导的从句谓语动词常用虚拟语气“(should)+动词原形”，但如果表示的事实，谓语动词就不用虚拟•Itisapitythatyoushouldhavetoleave.•很遗憾你不得不离开•Itisapitythatyouleft.•遗憾的是你离开了•3)It+be+过去分词+that从句•Itissaidthat...据说。。。•Itisreportedthat...据报道。。。•Itisbelievedthat...据认为。。。•Itisannouncedthat...据宣布。。。•Itmustbepointedoutthat...必须指出。。。•Ithasbeenprovedthat...已证明。。。•Itisestimatedthat...据估计。。。•Itmustbeadmittedthat...必须承认。。。•Itcanthusbecoucludedthat...可以由此得出结论。。。•Itwasreportedthattheyhadbroughtdowntwoenemyplanes.(击落飞机)•注意：如果过去分词表示“建议、命令、愿望”等含义的词，从句用虚拟语气“(should)+动词原形”•suggested建议的ordered命令的•requested要求的desired希望的•demanded要求的required要求的•recommended建议的decided决定的•insisted坚决要求的commanded命令的•Itisrecommendedthattheproject(should)notstartuntilallthepreparationshavebeenmade.•Itwassuggestedthathe(should)jointheclubactivities.•4)It+不及物动词+that从句，此句型中的that从句可以看做是句子的主语，但不能放句首，其句型为：•Itseemsthat...好像是。。。•Ithappenedthat...碰巧。。。•Itfollowsthat..由此可见。。。•Itmattersthat...要紧的是。。。•Itoccurredtomethat...我突然想到。。。•Itstruckmethat...我突然想到。。。•Didn'titoccurtoyouthatyourhusbandmightbelate?•Itissaidthattheyareahappypair.it用作宾语it作宾语，指代前面提到的一样东西、一个动物、一个婴儿或一件事情Didyouseethesnake?--Yes,Isawit.Howaboutthebaby?-I'lltakecareofit.Haveyougotmyexpressmail?-Yes,I'vegotit.IfIhaveimprovedinanyway,Ioweitalltoyou.•it作形式宾语，常用在下列动词后：consider,think,find,•count(把...认为),feel,judge•有下列几个常见句型：•1.主语+及物动词+it+形容词(作宾补)+不定式(真正宾语)•常见形容词有：•possible很可能difficult困难的•impossible不可能wise明智的•unwise不明智的necessary必要的•interesting有趣better更好些•wrong错误的•Theyjudgeditbettertoputoffthemeeting.•Ifeltitnecessarytomakeeverythingclear.•2.主语+及物动词+it+名词(作宾补)+不定式(真正宾语)•常见名词有•one'sduty某人的职责anhonour非常荣幸•commonknowledge常识•aquestion问题one'sbusiness某人的事•awonder是个奇迹nowonder不足为奇•goodnews好消息ashame可耻•apity遗憾•I'llmakeitmybusinesstohelpher.•Idon'tthinkitaquestionforhimtofinisheverythinginoneweek.•3.主语+及物动词+it+名词/形容词/过去分词(作宾补)+that从句(真正宾语)•常见名词有：•one'sduty某人的职责anhonour非常荣幸•commonknowledge常识•aquestion问题one'sbusiness某人的事•awonder是个奇迹nowonder不足为奇•goodnews好消息ashame可耻•apity遗憾常见形容词有：possible很可能difficult困难的impossible不可能wise明智的unwise不明智的necessary必要的interesting有趣better更好些wrong错误的•Theykeptitquietthathewasdead.•Weallthinkitawonderthattheyfinishedtheprojectinsuchashorttime.•Wehearditsaidthatthemeetingwouldbepostponed.•4.主语+及物动词+it+名词/形容词(作宾补)+动名词(真正宾语)•在此句型中常见的形容词及名词有：•nogood,nouse,awasteroftime,fun,hardwork,apity,•awonder,dangerous,difficult,senseless,•useless,foolish,nice,tiring,funny,hard,•interesting,worth,worthwhile,terrible•Hefounditnousewritingtohim.•Ithinkitdangerousswimminginsuchadeepriver.•5.it作宾语，用在某些特殊句型中•Seetoitthatyouarenotlateagain.•注意别再迟到了•Youcanputitthatitwasarrangedbefore.•你可以说这是以前安排的•Youmanydependuponitthatweshallneverloseheart.•你放心我们绝不会灰心•I'dappreciateitifyouwouldliketoteachmehowtousethecomputer.•句型为appreciate/like/love/hate+it+if/th