动词不定式、动名词用法要点讲解

动词不定式、动名词用法要点讲解一、作主语⒈不定式作主语动词不定式作主语时，句子的谓语动词常用单数，其位置有以下两种：(1)把不定式置于句首。如：Togettherebybikewilltakeushalfanhour.(2)用it作形式主语，把真正的主语不定式置于句后，常用于下列句式中。如：①It＋be＋名词＋todoIt'sourdutytotakegoodcareoftheold.②Ittakessb+sometime+todoHowlongdidittakeyoutofinishthework?③It＋be＋形容词＋forsb＋todoItisdifficultforustofinishwritingthecompositioninaquarterofanhour.④It＋be＋形容词＋ofsb＋todoItisstupidofyoutowritedowneverythingtheteachersays.⑤Itseems(appears)＋形容词＋todoItseemedimpossibletosavemoney.在句型③中，常用表示客观情况的形容词，如：difficult,easy,hard,important,impossible,necessary等；在句型④中，常用careless,clever,good,foolish,honest,kind,lazy,nice,right,silly,stupid,wise等表示赞扬或批评的词。在不定式前的sb，可看作其逻辑主语。这一句式有时相当于Sbis＋形容词＋todo句式，如：It'skindofyoutohelpmewithmyEnglish.=YouarekindtohelpmewithmyEnglish.⒉动名词作主语Learningwithoutpracticeisnogood.动名词作主语时，也常用It句式。如：①It's+nogood(nouse,fun,apleasure,awasteoftime)+doing…It'snogoodreadingindimlight.It'snousesittingherewaiting.②It's＋形容词＋doingIt'sdangerousswimmingintheseainwindydays.这样用的形容词有expensive,nice,tiring等，但important,necessary则不适用于这种结构，应用不定式代替，如：It'simportantforyoutokeepfit.③Thereisno+doingThereisnosayingwhatwillhappennext.在这一结构中，动名词后常带宾语，相当于It'simpossibleto…结构。⒊动词不定式和动名词作主语的区别①不定式作主语经常表示具体动作，常与特定的动作执行者联系在一起；而动名词作主语经常表示抽象动作，经常不与特定的动作执行者联系在一起。如：It'snogoodeatingtoomuchfat.It'snogoodforyoutoeatsomuchfat.②动名词结构作主语，可以用名词或代词属格形式作逻辑主语。如：It'snouseyourpretendingthatyoudidn'tknowtherules.二、作宾语⒈不定式作宾语①以下动词后，只能跟不定式作宾语。如：agree,ask,aim,arrange,choose,decide,demand,expect,fail,help,hope,lean,long,manage,offer,plan,prepare,pretend,promise,refuse,wish等，这些词大部分可接that引导的从句。如：Idecidedtoaskformymoneyback.IdecidedthatIwouldaskformymoneyback.Whenourvisittothefarmwasover,weexpectedtostartbackonfoot.Whenourvisittothefarmwasover,weexpectedthatwewouldstartbackonfoot.②当复合宾语中的宾语是不定式时，先用形式宾语it代替不定式，把不定式置于补语之后，即：主语＋动词＋it＋补语＋todo句式。如:Wethinkitquiteimportantforustolearnaforeignlanguagewell.Hefeelsithisdutytohelpthepoor.③介词but,except,besides+todo(do)在这种句型中，如介词前有动词do，后面应接不带to的不定式；如无do，则接to不定式，即带do不带to，带to不带do。如：Theenemysoldiershadnochoicebuttogivein.OnSundayafternoonIhadnothingtodobutwatchTV.⒉动名词作宾语①以下动词后，只能接动名词作宾语，如：admit,appreciate,consider,delay,enjoy,finish,keep,imagine,mind,miss,practise,resist,risk,save,suggest,don'tmind,giveup,insist,on,putoff等。如：Isuggestspendingoursummervacationinaseasidetown.Youmustgiveupsmoking,foritdoestoomuchharmtoyourhealth.②动名词作介词的宾语Ishouldgotoattendthebirthdaycelebrationinsteadofstayingathome.WhataboutinvitingLiJuntomakeaspeech?动名词前的介词有时可以省略，如：havedifficulty(in)doing,havenotrouble(in)doing,losenotime(in)doing,prevent/stop…(from)doing,thereisnouse(in)doing等。⒊部分动词后面，既可接动词不定式，也可接动名词作宾语，意义不变。如：begin,continue,start,hate,like,love,need,require,want等。在need,require,want后接-ing形式，表示被动意义，也可接不定式，但要用被动形式，如：Yourhandwritingneedsimproving(tobeimproved).hate,love,like接不定式表示特定的未来事件，接动名词表示目前正在进行的活动或一般的行为。在下列情况下，一般要用不定式：①hate,like,love前有would(should)时，如：I'dliketohaveacupofcoffee.②当谓语动词begin,continue,start等是进行式时，如：Thestudentsarestartingtoworkonthedifficultmathsproblem.③begin,continue,start与know,understand等状态动词连用时，如：Isoonbegantounderstandwhatwashappening.⒋advise,allow,encourage,forbid,permit等动词后接动名词作宾语，或带不定式作宾语补足语。如：Ourteachersdon'tpermitourswimminginthelake.Ourteachersdon'tpermitustoswiminthelake.⒌部分动词后接不定式或动名词时，意义差别较大，应根据句子语境选择使用。①forget,remember,regret后接不定式，表示现在或未来的动作，接动名词表示动作已经发生。如：Don'tforgetfoposttheletterforme.HaveyouforgottenmeetingherinBeijingAirport?Remembertoclosethewindowsbeforeyouleave.Irememberwritinghimaletterayearago.Weregrettotellyouthatallofyouarenotinvitedtoattendthemeeting.Theyregrettedorderingthesebooksfromabroad.②meantodo打算做某事doing意味着……Imeanttocatchupwiththeearlybus.Thismeanswastingalotofmoney.③trytodo设法尽力做某事doing试着做某事Youshouldtrytoovercomeyourshortcomings.Tryworkingoutthephysicsprobleminanotherway.④stoptodo停下一件事去做另一件事（不定式作目的状语）doing停止做某事Onthewaytotheairport,Istoppedtobuyapaper.You'dbetterstoparguinganddoasyouaretold.⑤can'thelpdoing禁不住……todo不能帮助干……Theycouldn'thelpjumpingupatthenews.SorryIhavelotsofworktodo.SoIcan'thelptomakeuptheroomforyou.⑥goontodo做不同的事或不同内容的事doing继续不停地做某事，指同一动作的继续Hewentontotalkaboutworldsituation.他接着又谈了世界形势。We'llgoonfightingsolongasthereisoppressionintheworld.⑦leaveofftodo离开某地去干什么（目的状语）doing停下某事It'stimetoleaveofftalkingandtostartacting.Theyleftofftogofishing.三、做表语不定式作表语表示具体动作或将来动作；动名词作表语表示抽象的一般行为。①Tobekindtotheenemyistobecrueltothepeople.②Mychiefpurposeistopointoutthedifficultiesofthematter.③WhatIwouldsuggestistoputoffthemeeting.当主语和表语都是不定式时，其含义一是条件，一是结果（例①）。当主语是aim,duty,hope,idea,mistake,plan,purpose,suggestion等为中心词的名词词组（例②）时，或以what引导的名词性分句（例③），不定式说明主语的内容。④Ourworkisservingthepeople.⑤Whathelikesistakingawalkaftersupper.⑥ThestorytoldbyMr.Wangisinteresting.④⑤句动名词作表语，与主语部分可以转换，如Servingthepeopleisoutwork,而⑥句中是现在分词作表语，说明主语的性质、状态，现在分词具有形容词的各种特征，另外，动名词作表语还应与进行时态区别开来。四、作定语⒈不定式作定语不定式在句中作定语，置于被修饰的名词或代词之后。如：①ThenexttraintoarriveisfromWashington.②Haveyouanythingtobetakentoyoursister?③Doyouhaveanythingtosayonthequestion?④Wouldyoupleasegivemesomepapertowriteon?⑤MywishtovisitFrancehascometrueatlast.不定式短语作定语和被修饰词之间表示以下关系：(1)表示将来的动