动词不定式讲解

一动词不定式：to+动词原形1.基本用法：可在句中作主、宾、表、定、状、补。1）作主语Togetupearlyisagoodhabit.It'ssonicetohearyourvoice.(it为形式主语)ItisimportantforustolearnEnglishwell.It’ssillyofyoutodosuchathing.HowtoimproveourEnglishisstillaproblem.2)作宾语Weallhopetoseeyou.TheyfoundithardtolearnChinese.（it为形式宾语）Idonotknowwhattodonext.（疑问词+不定式）HeaskedmehowtoimproveEnglish.（疑问词+不定式）3）作表语①一般情况Myworkistocleantheroomeveryday.Hisdreamistobeadoctor.Thequestionishowtoputitintopractice.问题是怎样把它付诸实施。Heseemedtohaveknownthenews.②如果主语是不定式，则表语也用不定式。例如：Toseeistobelieve.Seeingisbelieving.③作表语的不定式有时可省略符号to：这时主语部分必须含有动词do,而作表语的不定式则解释do的精确意思。AllIdidwas(to)givehimalittlehelp.Whatwewanttodonowis(to)havearest.4)作定语①不定式作定语时，被修饰的名词常为它的逻辑宾语。不定式与该名词存在逻辑上的动宾关系。Ihavesomeclothestowash.（后置定语）Hehassomethingimportanttotellyou.如果不定式是不及物动词，后面应有必要的介词。Givemeapentowritewith.Ineedawarmroomtolivein.②逻辑上的主谓关系。Hewasthefirstteachertocome.Ineedaboxtoholdmybooks.Isthereanyonetoanswermyquestion?Hewasthelaststudenttohavelefttheclassroom.(不定式完成式)③逻辑上的同位关系。Everyonehastherighttospeakatthemeeting=Everyonehastherightthathemay/canspeakatthemeeting.Dokeepyourpromisetowritetome.=Dokeepyourpromisethatyouwillwritetome.5)作状语①作目的状语Hewillgotothestationtomeethisfriend.IoftenreadChinaDailyinorderto(或soasto)improvemyEnglish.（inorderto可放在句首；soasto只能放在句中）。Icomehereonlytosaygood-byetoyou.②作结果状语Ihurriedtohishouseonlytofindhewasout.Heis(not)oldenoughtojointhearmy.It’stoolatetoplaybasketball.Hewassoangryastobeunabletospeak.③作原因状语Iwassurprisedtoseehimhere.Theywerepleasedtohearthegoodnews.Iamgladtomeetyou.④在形容词后作状语Thisquestioniseasytoanswer.6）作补语Hewantshissontobecomealawyer.Sheencouragedmetotryagain.Theypersuadedhimtogiveupsmoking.Theybelievehimtobewritinganewbook.他们认为他正在写一本新书。Hewantedthelettertobetypedatonce.Theletterwaswantedtobetypedatonce.(主补)注：有些动词后跟不带to的不定式作宾语补足语。常见的有：①感官动词feel,hear,see,watch,notice,observe②使役动词let,make,have③help：helpsb.do……或helpsb.todo……两种说法均可。Ioftenhearhimsingthissong.Thebossmadetheworkerswork12hoursaday.当此类句子改为被动语态时，要补上to.Heisoftenheardtosingthissong.Theworkersweremadetowork12hoursaday.☆在think,find,consider,discover等动词后常用tobe+adj.结构作宾补，有时tobe可省略。Weallthink/consider/find/discoverhim(tobe)kindandhonest.我们都认为/发现他既善良又诚实。2.不定式的时态/方式1)一般式：有时与谓语动词表示的动作同时发生，有时发生在谓语动词的动作之后。（todo）Heseemstoknowthis.Ihopetoseeyouagain.=IhopethatI'llseeyouagain.我希望再见到你。2)进行式：表示动作正在进行，与谓语动词表示的动作同时发生。(tobedoing)Heseemstobeeatingsomething.3)完成式：表示的动作发生在谓语动词表示的动作之前。(tohavedone)I'msorrytohavegivenyousomuchtrouble.Heseemstohavecaughtacold.4)完成进行式：(tohavebeendoing)Sheisknowntohavebeenworkingontheproblemformanyyears.Hepretendedtohavebeenstudying.3.动词不定式的否定式：nottodoTellhimnottoshutthewindow.ShepretendednottoseemewhenIpassedby.例1）Tellhim___thewindow.A.toshutnotB.nottoshutC.tonotshutD.notshut答案：B。tellsb.todosth的否定形式为tellsb.nottodosth..例2)Shepretended___mewhenIpassedby.A.nottoseeB.notseeingC.tonotseeD.havingnotseen答案：A。pretend后应接不定式。其否定形式为pretendnottodosth.。例3）Mrs.Smithwarnedherdaughter___afterdrinking.A.nevertodriveB.toneverdriverC.neverdrivingD.neverdrive答案：A。warnsb.todosth.的否定形式为warnsb.nottodosth.此处用的是否定词never.例4)Theboywantedtoridehisbicycleinthestreet，buthismothertoldhim____.A.nottoB.nottodoC.notdoitD.donotto答案：A。notto为nottodoit的省略形式。例5)Thepatientwaswarned___oilyfoodaftertheoperation.A.toeatnoB.eatingnotC.nottoeatD.noteating答案：C。此处为warnsb.todo的被动否定形式，即bewarnednottodo。4.动词不定式的省略1）不定式在使役动词let,have,make和感官动词see,watch,notice,observe,hear,smell,feel,find等后作宾补时，省略to。help可带to，也可不带to→helpsb(to)dosth。2)Whynot后面接不带to的不定式。常用来表建议。Whynothaveabreak?3）but和except：but/except前的部分出现实义动词do时，其后面出现的动词不定式可以不带to。Hewantstobelieveanythingbuttotakethemedicine.比较：but前有实义动词do时，but后的不定式需要省去to.如：LastnightIdidnothingbut(to)watchTV.Hedoeseverythingexcept(to)work.4)由and,or或than连接的两个不定式，第二个不定式的to可以省去。例如：HewantstomovetoFranceandmarrythegirl.5）通常在discover,imagine,suppose,think,understand等词后，可以省去tobe：Heissupposed(tobe)anhonestman.例1)----Iusuallygotherebytrain.----Whynot___byboatforachange?A.totrygoingB.tryingtogoC.totryandgoD.trygoing答案：D.whynot后面接不带to的不定式，因此选D。例2）Pauldoesn'thavetobemade___.Healwaysworkshard.A.learnB.tolearnC.learnedD.learning答案：B.make后接不带to的动词不定式作宾补，当句子是被动语态时，to要补上。5不定式特殊句型soasto：表示目的；其否定式是soasnottodo。IoftenreadChinaDailysoastoimprovemyEnglish.Tomkeptquietabouttheaccidentsoasnottolosehisjob.汤姆对事故保持沉默是为了不丢掉他的工作。Goinquietlysoasnottowakethebaby.轻点进去，别惊醒了婴儿。注：同样表示目的，inorderto可放在句首，但soasto不可放在句首。6不定式特殊句型too…to1）too…to太…以至不能…Heistooexcitedtospeak.I'mafraidtheboxistooheavyforyoutocarryit。2)如too前有否定词，则表达一种委婉含义，意为不太。It'snevertoolatetomend.改过不嫌晚。3)当too前面有only,all,but时，意思是“非常…”，相当于very。I'monlytoopleasedtobeabletohelpyou.我非常高兴能帮助你。Hewasbuttooeagertogohome.他非常想回家。7.常见后接动名词与不定式语义不同的有10组：(1)stoptodostopdoing(2)forgettodoforgetdoing(3)remembertodorememberdoing(4)regrettodo（当时或现在遗憾地做什么）regretdoing（做了某事而感到遗憾/后悔）(5)ceasetodoceasedoing(同stop)(6)trytodotrydoing(7)goontodogoondoing(8)beafraidtodo（因害怕而不敢做……）beafraiddoing（害怕、担心某事可能发生）(9)beinterestedtodo（对做某事感兴趣，想了解某事）beinterested(in)doing（对某种想法感兴趣，doing通常为想法等）(10)meantodo（打算，意欲）meandoing（意味着）例1.Wearenotinterested_________tos