1八年级英语动词不定式用法梳理动词不定式是由“不定式符号to+动词原形”构成的一种非谓语动词结构。有些动词不定式不带to,动词不定式可以作句子的主语、表语、宾语、定语、补语、状语或单独使用。不定式保留动词的某些特性,可以有自己的宾语、状语等。动词不定式和它后面的宾语、状语等一起构成短语,叫作不定式短语。一、用作主语多数情况用it作形式主语,把真正的主语——动词不定式置于句末,特别是不定式短语较长时。动词不定式作主语,谓语动词用第三人称单数形式。疑问词+不定式短语作主语可置于句首,复合不定式结构作主语常置于句末。如:1.Itisourdutytotryourbesttodealwiththeseproblems.2.Theheadteachersaiditwasnecessarytotalkwithhismother.3.HowtolearnEnglishwellisimportant.4.Toseeistobelieve.(眼见为实;百闻不如一见)二、用作表语动词不定式作表语,常说明主语的内容、性质、特征。如:1.ThebestwayistojoinanEnglishclub.2.Thefirstthingistolistentotheteachercarefully.三、用作宾语1.可以接带to的动词不定式作宾语的动词主要有:要求选择2同意(ask,choose,agree),期望决定学习(expect,hope,decide,learn),宁可假装知道(prefer,pretend,know),希望想要愿意(wish,want,wouldlike/love)。如:1)Wedecidedtotalktosomestudentsaboutwhytheygothere.2)Hepreferstoeatwhitebreadandrice.3)IdlovetovisitMexico.2.动词decide,know,learn,show,teach,tell...,介词结构on...可用疑问词带to的不定式短语作宾语,但why后面的不定式不带to。如:1)Couldyoupleasetellmewheretoparkmycar?2)Itgivesadviceonwhattodoinlotsofdifferentsituations.3.动词feel,find,make,think等后面,可以用it作形式宾语代替真正的宾语——动词不定式,句子结构是...feel/find/make/...it+adj./n.+todo...。如:4.感知动词like,love,know等一般不用进行时态。5.后接动词不定式或ving形式作宾语,意思差别较大的动词有forget,remember等。后接不定式作宾语,表动作尚未发生;后接ving形式作宾语,表动作已经发生。stoptodo停下来做另外一件事,todo是目的状语;stopdoing停止做、不做当前这件事,doing是宾语。trytodo尽力做,trydoing试试看;goontodo接着做另外的事,goondoing继续做原3来的事。如:1)WhenIlefthome,Iforgottobringitwithme.2)Istoppedusingthemlastyear.四、用作定语1.句子的主语或宾语是动词不定式的逻辑主语,不定式与其所修饰的名词、代词等存在逻辑的动宾关系.1)Ihavesomanyclothestowashtoday.2)Ican’tthinkofanygoodadvicetogiveher.3)Wehavenohousestolivein.2.动词不定式所修饰的名词是place,time,way等时,不定式与这些名词呈现出动状关系或同位关系。如:1)Heneedstimetodohomework.2)Hewantstoknowthebestwaytotravelaroundthecity.3.在“therebe...”句型里,句子的主语是动词不定式动作的对象:1)There’sjustsomuchtoseeanddohere.2)...buttherearestillmanythingstodothe五、用作宾语补足语1.带to的动词不定式作宾语补足语的动词主要有:要求允许提议(ask,allow,,advise),期望邀请鼓励(expect,,invite,encourage),教导告诉想要(teach,tell,want),等待希望愿意(waitfor,wish,wouldlike/love)。如:41)Idinvitehertohavedinneratmyhouse.2Weshouldallowthechildrentochoosetheirownclothes.2.动词不定式作补语,在主动语态句里不带to,被动语态句里带to时多数动词是感官动词和使役动词,包括四“看”:lookat,observe,see,watch,三“让”:have,let,make,二“听”:hear,listento,一“感觉”:feel,一“注意”:notice。如:1)Thispicturemakesmefeelexcited!2)WesawLiuYuplaybaseballlastweek.3.help后接动词不定式作补语,to可带可不带。1)theycanhelpyoutolearnEnglish.2)UsingemailEnglishhelpsyouwritequickly.六、用作状语1.目的状语,置于句首或句末,置于句首时常表示强调。如:1)Inordertocatchtheearlybus,shegotupveryearly.2)Agroupofyoungpeoplegottogethertodiscussthisquestion.3)Shecametothiscitytovisitherdaughter.2.原因状语,多见于“sb.+be+adj.+todo...”结构句中。如:1)Ifeelveryluckytohavehim.2)heranoutofmoneytobuyoldbikes.3.结果状语,多见于“too...to”,“enoughto...”结构句中。如:51)I’mtootiredtodoitwell.2)Theroomisbigenoughforthreepeopletolivein.七、动词不定式的复合结构动词不定式的复合结构是“for/ofsb.todosth.”,for/of引出不定式动作的逻辑主语。这种结构在句子中可以作主语、宾语、表语、定语、状语等。不定式复合结构的介词用for还是of,主要决定于前面形容词的性质。一般说来,of前面的形容词是careful,clever,foolish,good,kind,nice,wise等,既说明人的特性,又说明不定式动作的特性。for前面的形容词是dangerous,difficult,easy,hard,heavy,important,interesting,necessary等,一般说明不定式动作的特性,前面如果是名词用for。如:1.It’sagoodideaforparentstoallowchildrentostudyingroupsduringtheevening.2.It’swiseofhimtodoitwell.3)Isitinterestingforthebabytoplaywithapetdog?八、带疑问词的不定式短语动词不定式前面可以带疑问代词what,which,who或疑问副词how,when,where,why等。这种结构起名词的作用,在句子里用作宾语、主语、表语等,或者单独使用。要注意的是,why后面的不定式不带to。如:1.用作句子的成分。61)Idon’tknowwhattotrynext.(作宾语)2)Wheretogoisnotdecidedyet.(作主语)2.单独使用时相当于一个特殊疑问句。1)Whattodonext?(=Whatwillwe/youdonext?2)Whygothere?(=Whydowe/yougothere?九、动词不定式的否定式不定式的否定式是not/nevertodo...,不带to的不定式的否定式是not/neverdo...如:1.Theydecidenottotalktoeachother.2.Hisparentstellhimnevertoplaysoccerinthestreet.随堂练习一动词填空。1.I’mgoingtolistentotheradio.Please____(nottalk)anymore.2.Thestudents____(do)theirhomeworkfromfourtofivethisafternoon.3.Thestudents____(be)busynow.They____(have)anEnglishexamnextMonday.4.Marymust____(look)afterherlittlesisterbecausesheistooyoung.5.____(he)youwaitingforabusnow?6.Thiscoatisverycheap.I____(take)itnow.7.I’lltellhimaboutitwhenhe____(come)back.8.Couldyoutellmehow.I____(canget)toNo3Middleschool.9.He____saidthatthenewteacher____(give)thestudentsanEnglishlessonnow.10.I____(milk)acowthreetimes.11.Edison’smother____(teach)himherself.712.He____(watch)TVonceaweek.13.Don’tspeakloudly.Thebaby____(sleep).14.Iwon’tgooutuntil.I____(finish)myhomework.15.Couldyoutellmewhenthetrain____(arrive).16.Ioftenhearthesoundofchildren____(read)Englishintheroom.17.Heaskedme____(help)himwithhisEnglishthisevening.18.Theirworkis____(clean)thestreets.19.Didheenjoy____(work)inChina.20.Wewillstayathomeifit_____(rain)tomorrow.21.Bequiet!Theboy____(sing)anEnglishsong.22._____you_____yourhomeworkyet(start)?23.Who____(teach)themEnglishlastterm.24.There_____(be)atelephonecallforyoujustnow.25.Pleasekeepeverything____(clean).26.Peterwon’thavearestuntilhe____(finish)hiswork.27.IwatchedTV,soI____(forget)_____(do)myhomework.28.WhenI____(walk)alongtheriver,Imetmyfriend,Tom.29.WhenMothercame,thelittlegirl____(play)withacat.30.WhenIwasfive,I____(get)toknowtheearth____(move)aroundthesun.31.They_____(see)aboy_____(fall)intotheriverwhilethey__