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非谓语动词动词不定式构成不定式由’to+动词原形’构成，是非谓语动词的一种，即不能做谓语，没有人称和数的变化。不定式加上它的宾语和状语构成不定式短语，可做谓语以外的其他句子成分。不定式的作用1、作主语1）不定式todo直接放在句首作主语•Tofinishtheworkintenminutesisveryhard.•Toloseyourheartmeansfailure.•Todothatsortofthingisfoolish.续上：•Tomasteraforeignlanguageisreallyimportantnowadays.•Togiveupsmokingisright.不定式的作用2）It作形式主语放句首，真正的主语不定式放在句后。•Itisveryhardtofinishtheworkintenminutes.•Itmeansfailuretoloseyourheart.不定式的作用It作形式主语常用句式:a.It+be+名词+todo•Itisyourdutytoobeytherulesatschool.•It’sgoodmannerstohelpothersintrouble.不定式的作用b.Ittakessb.+sometime+todo•IttakestimeandefforttomasterEnglish.•Ittookustwohourstofinishthejob.•Ittakesmehalfanhourtogotoschool.不定式的作用c.It+be+形容词+for+sb+todo•ItisimpossibleforustomasterEnglishinashorttime.•Itisagainsttheregulationforyoutoparkyourcarhere不定式的作用d.It+be+形容词+ofsb+todo•It’skindofyoutohelpmewithmymath.(形容词常用clever,good,foolish,honest,kind,nice,silly,stupid，wise等表示赞扬或批评的词。)不定式的作用2.作表语•Yourjobistowashdishes.•Toseeistobelieve眼见为实•Allyouhavetodoistofinishitquickly续上：•Ourmaintaskistodevelopthestudents’abilitytosolveproblems.•Herwishistobecomeadoctor.不定式的作用3、作宾语1）V+todo•Shepromisedtogivehimanotherchance.•Ihopetoseeyouagain.•HedecidestolearnEnglishwell.不定式的作用以下动词后常跟todo形式：agree,demand,ask,decide,expect，hope，want,offer,plan,pretend，promise,afford,prepare,refuse,manage,fail,dare,fear,swear,choose等。例句：•Hedidn’thaveanymoney,sohedecidedtolookforjob.•Shepretendedtobeill.•Hemanagedtofinishhishomeworkintime.不定式的作用2）少数介词后面可跟不定式作宾语•Ithasnochoicebuttoliedownandsleep.•Theyhavenochoicebuttostaythere.•Theydidn’topentheirmouthsexcepttocomplain.不定式的作用但是，Can’tbut,can’tchoosebut,can’thelpbut,donothingbut,ratherthan,hadbetter等之后省略to。•There’snothingtodoexcept/butwaittillitstopsraining.•Hedoesnothingbutplayallday.不定式的作用3)作宾语补足语Theteachertoldhisstudentstopaymoreattentiontotheirpronunciation.Iwouldliketheproblemtobediscussedatthenextmeeting.续上：•Iwarnedthepatientnottodrinkcoldwateraftertheoperation.•Sheaskedmetostaythere.不定式的作用注意:以下动词：feel,hear,listento,make,have,let,seewatch,notice,lookat,observe与不带to的不定式连用。•Theteachermademeanswerthequestion.•Wewatchedthemplayfootball.•Iheardthemsingapopsong不定式的作用注意：不定式作宾补改成被动语态，to不可省略。•Iheardthemsingapopsong.Theywereheardtosingapopsong.•Isawhimcrosstheroad.Hewasseentocrosstheroad.不定式的作用4.作定语,放在被修饰词后面。•Doyouhaveanythingtosay?•Bettywasthefirsttoknowthetruth.•Hehasnotimetoseethefilm.注意：如果动词不定式是不及物动词，后面须加相应的介词。•Wefoundahousetolivein.•Hewantstofindachairtositon.•Thisisaninterestingpicturetolookat.不定式的作用5.作状语1）表目的：ShecameheretostudyEnglish.Heworkeddayandnighttogetthemoney.Shesoldherhairtobuythewatch.不定式的作用注意：不定式放句首时，逻辑主语与句子主语要一致。•Tosavemoney,everymeanshasbeetried.(错)Tosavemoney,hehastriedeverymeans.（对）•TolearnEnglishwell,adictionaryisneeded.（错）TolearnEnglishwell,weneedadictionary.(对)2）表结果•I’mtootiredtowalkanyfurthertonight•Hehurriedtothestationonlytofindthatthetrainhadleft.•TheyaretooyoungtounderstandwhatIhavesaid.3）表原因•Theyjumpedwithjoytohearthenews.•Theywereverysadtohearthenews.不定式的作用6.动词不定式短语可以和疑问词what，which，how，where，when等连用•Idon’tknowwhattodo.•Couldyoutellmewheretobuythebook.•Hedidn’tknowwhattosaywhenhesawJack.动词不定式的否定形式只须在to前加not：•Myfatherdecidedtotakeupthejob.Myfatherdecidednottotakeupthejob.•Idecidedtoaskhimagain.Idecidednottoaskhimagain.谢谢！