1动词不定式用法归纳动词不定式没有人称和数的变化,在句中不能独立作谓语。但动词不定式具有名词、形容词和副词特征,在句中可以作主语、宾语、宾语补足语、定语、表语和状语等多种成分。另外,动词不定式具有动词特点,可以有自己的宾语和状语,组成动词不定式短语。动词不定式的肯定形式是to+do;其否定形式是notto+do。下面以动词不定式在句中的作用来予以详细说明。1.作主语可以直接作主语。如:Toseeistobelieve.但在英语中,常用it作形式主语,真正的主语即动词不定式放在后面。如:It'swrongtoplaytricksonotherpeople.It'sourdutytokeepourenvironmentcleanandtidy.规律:动词不定式在句中作主语时,常放在Itis+adj.(形容词)+todosth.或Itis+n.(名词)+todosth.it仅作形式主语。2.作宾语want,decide,agree等动词后面跟并且只能跟不定式。如:Weagreedtostartearly.Shewantstobeadoctor.而love,like,begin,start,hate,prefer等词后面可以接不定式,还可以接动名词,意思无很大区别。提示:likedoing指经常性动作,而liketodo指一次性的动作。如:Ilikeswimming,butIdon'tliketoswimnow.我喜欢游泳,但我现在不想游。特别注意:stop,forget,remember,goon,try等词或短语后面可以接不定式。但后面接不定式和接动名词意思大不相同。如:1)stoptodosth.停止一件事,去做另一件事。Stopdoingsth.停止正在做的事。例:Whentheteachercamein,thestudentsstoppedtalking;whenhecameout,thestudentsstoppedtotalk.当老师走进来时,学生们停止说话;当老师走出去时,学生们又开始说话。2)思考:forget,remember,goon,try等词或短语后面接不定式和动名词用法有何区别?在find/feel+it+adj.+todosth.句型中,it是形式宾语,真正的宾语是后面的动词不定式。如:Themandownstairsfounditdifficulttogettosleep.Ifeeliteasytorecitethetext.3.作宾语补足语tell,ask,want,order,teach,invite,warn,wish,help,get,wish,help等词后面常接不定式作宾补。如:Itellhimnottogotherebybus.Edison'smothertaughthimtoreadandwrite.let,make,have,see,hear,feel,watch,notice后面接不带to的不定式作宾补。如:Thebossmakesthemwork16hoursaday.Iheardhersinginthenextroom.提示:若变成被动语态,在上述结构中,不定式符号to要加上。如:Theyaremadetowork16hoursadaybytheboss.Shewasheardtosinginthenextroom.4.作定语:放在被修饰的名词、代词后面.例:Ihavealotofworktodo.Thedoctorsaidhecoulddonothingtohelptheboy.规律:动词不定式若在句中作定语,常放在被修饰的名词、代词之后。提示:如果动词不定式和前面所修饰的词构成动宾关系,若动词是不及物动词,切记不要忘掉介词。如:Ihaveasmallbedroomtolivein.Haveyougotsomepenstowritewith?5.表语:放在连系动词be后面.例:Hiswishistobecomea2scientist.Thefirstimportantthingistosavethesoldiers'lives.当务之急是抢救战士们的生命。规律:动词不定式在句中作表语时,通常对连系动词前面的名词进行诠释说明。6.作状语目的状语:放在go,come,use,live,inorder等词后面。如:Icometoseeyou.Herunsfastinordertogetthereintime.原因状语:放在sorry,glad,surprised,disappointed,excited等词后面。如:Iamgladtoseeyouhere.Iamsorrytotroubleyou.作结果状语。如:Someoftheapplesarehardtoreach.Theroomislargeenoughtohold1000people.7.与what,who,whose,when,where,how等疑问词连用,作宾语、宾语补足语、主语等。如:Idon'tknowwhattodonext.(宾语)Hetaughtushowtousethecomputer.(宾语补足语)It'sstillaquestionhowtogetthere.(主语)热身练习:根据句意,用括号内所给动词的适当形式填空。1.It'stimeforus_____(have)supper.2.Wouldyoulike_____(go)shoppingwithme?3.Ittookushalfanhour_____(work)outtheproblem.4.Heisoldenough_____(join)thearmy.5.Ifeelstrange_____(have)atwinsister.6.Iamveryglad_____(meet)youhere.7.Theyprefer_____(stay)athomeratherthangoout.8.Wesawthem_____(come)intotheroomjustnow.9.Whathesaidmademe_____(feel)sorry.10.Iamsorry.Iforgot_____(tell)youthenews.11.Hisplanis_____(spend)afewdaysinthemountains.12.Haveyougotanything_____(say)?13.Haveyoudecidedwhichone_____(choose)?14.Doyouknowwhen_____(start)?15.Heistooweak_____(carry)thebigstone.Key:1.tohave;2.togo3.towork4.tojoin5.tohave6.tomeet7.tostay8.come9.feel10.totell11.tospend12.tosay13.tochoose14.tostart15.tocarry