英语四级语法基础知识必备（05）

被动式:当不定式的逻辑上的主语是不定式所表示的动作的承受者时不定式一般要用被动形式.Itisanhonourformetobeaskedtospeakhere.Shehatedtobeflattered.Hewantedthelettertobetypedatonce.Thisisboundtobefoundout.Therearealotofthingstobedone.Shewastooyoungtobeassignedsuchwork.功用:不定式可以作主语(a)宾语(b)表语(c)定语(d)或是状语(e).a.Toscoldherwouldnotbejust.b.Weareplanningtobuildareservoirhere.c.Oneofourmaintasksnowistomechanizeagriculture.d.Doyouhaveanythingtodeclare?e.Wehaveetolearnfromyou.不带to的不定式:在“动词+宾语+不定式”结构中如果动词是表示感觉意义的seehearwatch***ellfeelnotice等或是表示“致使”意义的havemakelet等其后的不定式结构不带to.Johnmadehertellhimeverything.这类结构转换为被动语态时后面的不带to的不定式一般还原为带to的不定式.Shewasmadetotellhimeverything.在hadbetterhadbestwouldratherwouldsoonerwouldjustassoonmight(just)aswellcannotbut等搭配之后动词不定式也不带to.I'drathernothaveeggsandbaconforbreakfast.Theycannotbutaccepthisterm.在makedomakebelieveletdropletfAllletflyletslipletdriveletgooflettherebehearsayheartellleavegoof等固定搭配中用不带to的动词不定式.Johnletflyatorrentofabuseatme.I'veheardtellofhim.在动词help(或help+宾语)之后可用不带to的不定式也可用带to的不定式.CanIhelp(to)liftthisheavybox?在介词exceptbut之后如果其前有动词do的某种形式不定式一般不带to反之带to.Thereisnothingtodoexceptwaittillitstopsraining.Smithwilldoanythingbutworkonafarm.There'snochoicebuttowaittillitstopsraining.连词ratherthansoonerthan置于句首时其后的不定式不带to.Ratherthanpushthebookbackashewantedtodoheforcedhimselftopickitup.出现在句中其他位置时其后的不定式有时带to有时不带to.Hedecidedtowriteratherthantelephone.Themanagerbelievesitisimportanttoinvestinnewmachineryratherthantoincreasewages.用作补语的动词不定式如果主语是由“all+关系分句”，“thing+关系分句”，“what分句”或“thing+不定式结构”等构成，并带有do的某种形式，这时，作为主语补语的不定式可以省to，也可以不省.Whathewilldois(to)spoilthewholething.AllyoudonowispletetheformTheonlythingIcandonowisgoonbythingtodonowisclearupthismess.TheleastIcandoisdriveeverybodyelseclosertotheissue.