2021年大学英语四级常用语法精选(5).docx

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2021年大学英语四级常用语法精选(5)

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.Wehavecometolearnfromyou.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see,hear,watch,smell,feel,notice等,或是表示“致使”意义的have,make,let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hadbetter,hadbest,wouldrather,wouldsooner,wouldjustassoon,might(just)aswell,cannotbut等搭配之后,动词不定式也不带to.I'drathernothaveeggsandbaconforbreakfast.Theycannotbutaccepthisterm.在makedo,makebelieve,letdrop,letfall,letfly,letslip,letdrive,letgoof,lettherebe,hearsay,heartell,leavegoof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except,but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ratherthan,soonerthan置于句首时,其后的不定式不带to.Ratherthanpushthebookbackashewantedtodo,heforcedhimselftopickitup.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.AllyoudonowiscompletetheformTheonlythingIcandonowisgoonbymyself.Thethingtodonowisclearupthismess.TheleastIcandoisdriveeverybodyelseclosertotheissue.