不定式属于非限定动词。它除了不能做谓语外，在句中可以充当任何成分，可以作主语、表语、宾语、补语、定语和状语。1.作主语:往往放在谓语动词之后,用it作形式主语,为了避免句子头重脚轻。e.g.Toseeistobelieve.Itisrighttogiveupsmoking.2.作宾语:作宾语时如果还带有宾语补足语,往往把不定式放在补足语之后,而用it作形式宾语。e.g.Hewantedtogo.IfinditinterestingtostudyEnglish.3.做宾语补足语e.g.Heaskedmetodotheworkwithhim.在feel,hear,listento,lookat,notice,observe,see,watch,have,let,make等词后的补足语中,不定式不带to。不定式作宾语补足语省略to的情况有下列口诀:一感二听三让五看半帮助。但是这些句子如果变成被动结构时,就必须带上to。e.g.Ioftenhearhimsingthesong.Heisoftenheardtosingthesong.4.作定语e.g.Ihavesomebooksforyoutoread.当作定语的不定式如果是不及物动词,或者不定式所修饰的名词或代词是不定式动作的地点,工具等时,不定式后面必须有相应的介词。e.g.Heislookingforaroomtolivein.当作定语的不定式所修饰的名词或代词是不定式动作的承受者时,不定式即可以用主动语态,也可以用被动语态。但含义有所不同。试比较:Haveyouanythingtosend?你有什么东西要(自己)寄吗?Haveyouanythingtobesent?你有什么东西要(我或别人)寄吗?5.作状语,表示目的,原因,结果或条件。e.g.Icameheretoseeyou.Wewereveryexcitedtofindnobodythere.Hehurriedtotheschooltofindnobodythere.Tolookathim,youwouldlikehim.目的原因结果条件6.作表语e.g.Myjobistohelpthepatient.注意注意::主,表都是不定式,前者为条件,后者为目的或结果。e.g.Tolearnalanguageistouseit.不定式的时态有：一般式、进行时、完成式和完成进行式。当不定式的逻辑主语是不定式动作的承受者时，不定式就要用被动形式。不定式的时态和语态1.不定式的一般式所表示的动作通常与谓语的动作(状态)同时(或几乎同时)发生,或是在它之后发生。主动：e.g.I’mgladtomeetyou.被动：e.g.Therewasnothingtobedone.2.如果谓语表示的动作发生时,不定式表示的动作正在进行,这时要用进行时。e.g.Iamverygladtobeworkingwithyou.3.如果不定式的动作发生在谓语动词之前,就要用完成时。主动：e.g.I’msorrytohavekeptyouwaitingsolong.被动：e.g.Theroomwassaidtohavebeencleaned.从A、B、C、D四个选项中，选出可以填入空白处的最佳选项。1.Thereweremanytalentedactorsouttherejustwaiting______.A.todiscoverB.tobediscoveredC.discoveredD.beingdiscoveredHaveatryHaveatry2.Ihavealotofreadings______beforetheendofthisterm.A.completingB.tocompleteC.completedD.beingcompleted3.Hisfirstbook______nextmonthisbasedonatruestory.A.publishedB.tobepublishedC.topublishD.beingpublished4.Withtheworldchangingfast,wehavesomethingnew______withallbyourselveseveryday.A.dealB.dealtC.todealD.dealing5.Ilikegettingupveryearlyinsummer.Themorningairissogood______.A.tobebreathedB.tobreatheC.breathingD.beingbreathed1.I’mtravellingduringasandstorm.It’sdangerous.2.Expertshopethattheywilllearnmoreaboutthemovementofthunderstorms.Rewritethesentencesusinginfinitivestructures.Itisdangeroustobetravelingduringasandstorm.Expertshopetolearnmoreaboutthemovementofthunderstorms.3.Weweretold,“Don’tleavethehouse.”4.Themenneedtocompletetheworkonthehousebytheendoftheweek.Weweretoldnottoleavethehouse.Theworkonthehouseneedstobecompleted(thework)bytheendoftheweek.5.Itseemsthatmosthouseshavebeendestroyedbythestorm.Mosthousesseemtohavebeendestroyedbythestorm.Puttheverbsinbracketsintothecorrectinfinitiveforms.1.Itisfrightening________(walk)intheroadinasandstorm.IhopeIreachhomesoon.2.Expertshope_______(learn)moreaboutthemovementofsandstorms.towalktolearn3.I’dlike__________(tell)aboutthesituationbeforenow.4.Theworkneeds_______________(complete)bythe...
