Grammar:动词不定式一．不定式的五种基本形式主动被动一般式todotobedone完成式tohavedonetohavebeendone进行式tobedoing不定式的否定形式：nottodo/nottohavedone/nottobedoing/nottobedone/nottohavebeendone不定式的进行式、完成式和被动式①不定式的进行式由tobe+V-ing构成，用来表示谓语动词动作发生时，不定式的动作正在进行。eg.Somestudentspretended____________(read)Englishwhentheteachercamein.②不定式完成式由tohave+V-ed构成，用来表示动作发生在谓语动作之前。eg.---IsBobstillperforming?---I’mafraidnot.Heissaid__________(leave)thestagealreadyashehasbecomeanofficial.③不定式的被动式分为一般式被动tobeV-ed和完成式被动tohavebeenV-ed。当不定式的逻辑主语是不定式所表示的动作的承受者时，不定式要用被动语态。eg.Itisanhonourforme_____________(invite)totheparty.Thebookissaid_______________________(translate)intomanylanguages.Allthesegiftsmustbemailedimmediately_____intimeforChristmas.A.inordertohavereceivedB.inordertoreceiveC.soastobereceivedD.soastobereceiving二.不定式句法功能1.作主语：Tofindatruefriendisdifficult.不定式短语作主语时，可以直接放在句首，但在很多情况下，尤其是在疑问句和感叹句中，往往放在谓语之后，而用先行代词it作形式主语Itisdifficulttofindatruefriend.Isitdifficulttofindatruefriend?Howdifficultitistofindatruefriend!不定式作主语常见句型：a)Itis+adj.(easy,important,difficult…)+todosth.b)Itis+n.(apity,apleasure,one’sduty,ashame)+todosth.eg.It’sapleasuretogoshoppingatweekends.c)Ittakes/needs/requires+sometime(hours,months,days,patience…)+todosth.eg.Itrequirespatiencetobeagoodteacher.2.作表语：当句子的主语是aim,idea,policy,question,suggestion,wish,task,duty,job,purpose等或者主语是what引导的名词性从句时，后面可以用不定式做表语，用以说明主语所包含内容。eg.Ourmostimportanttasknowistomakeaplan.注：作表语的不定式都带to，但当主语部分有实义动词do时，to可以省略。eg.Theonlythingwecandonowiswaitandsee.3.作宾语Theteachersaid“Remembertobringthebooktomorrow!”a)可以直接用不定式作宾语的动词很多，常见的有：agree,afford,tend,ask,decide,determine,expect,fail,hope,learn,intend,manage,offer,plan,promise,refuse,want,wish等当复合宾语中的宾语是不定式时，先用形式宾语it代替不定式，把不定式置于补语之后，即：主语＋动词＋it＋补语＋todo句式,常用动词有feel,think,find,believe,consider,make等。如:Hefeelsithisdutytohelpthepoor.Ithinkitdifficulttofindatruefriend.b)不定式一般不作介词的宾语，只有少数介词如but,except等后面可以跟不定式作宾语。一般情况下作介词宾语的不定式都带to，如果but或except前面有do,does,did,todo时，通常省略to。eg.Thebushadn’tcome.Wehadnochoicebuttowait.=Wecoulddonothingbutwait.4.宾语补足语在主语+谓语+宾语+宾补句型中，许多动词都可以接不定式作宾语补足语。a)通常作宾语补语的不定式要带to，常用于以下动词之后：ask,tell,advise,allow,permit,enable,expect,force,get,like,order,teach,want,invite,wish,beg等Youshouldgetthemtohelpyou.在谓语动词believe,find,think,feel,consider,suppose,imagine,prove等后面跟tobe…作宾补，不跟todo,有时tobe可省略①WeallbelieveJohn(tobe)honest.②Iconsiderhim(tobe)oneofthebestteachersofNo.1MiddleSchool.但当不定式是完成式时，to不能省略，如：Weconsiderhimtohavebeenfoolish.b)以下两类动词后跟不定式作宾补时不能带to①使役动词，如：let,have,make等②感官动词，如：see,watch,notice,lookat,listento,hear,feel,等Don’tletthechildrentroubleyou.Iheardsomeoneopenthedoor.但当这两类动词为被动态时，不定式就成了主补。作主补的不定式必须加上toHisfathermadehimgotobedearly.→Hewasmadetogotobedearlybyhisfather.动词...
