選必三Unit1Grammar動詞不定式（todo）(短語）作表語一、結構動詞不定式可以放在be,bee,sound,taste等系動詞后面作表語。二、用法1、動詞不定式作表語，表示主語的內容和目的。主語常常是表示意向、打算、計劃、任務的詞，如wish,idea,task,purpose,duty,dream,aim,goal,intention,hope,plan,ambition,decision,以及what引導的主語從句等。有時，根據表達的需要，在作表語的不定式前，還可添加疑問詞，包括what,who,how,when,where等。例如：Theproblemwashowtobegin.Eg：1.MygoalinthetermistoimprovemyEnglish.2.Herdreamistobeadmittedto/intoakeyuniversity.3.WhatIwanttodonowistoexpressmythanksforyoutooffermethejob.4.Ourdifficultyatpresentishowtofindthesolution.注意：不定式在作表語時，當前面的主語中有do的某種形式時，作表語的不定式可以省略to。1.Whatyoushoulddonextis(to)helphimwithhisEnglish。2.Theonlythinghecandonowis

(to)giveup

theplan.2、當主語包含定語從句且其先行詞為代詞all或者主語被only/first/one/least或形容詞最高級修飾時，系動詞后可接不定式作表語。Eg：Allhewantedwastobeleftalone.他只想一個人待著。TheleastIcandotohelpistolendheracar.我所能幫的最起碼的事是借給她一輛車。主語+be+todo表示將來/命令/禁止/注定發(fā)生/應該做。

1.PresidentBidenistovisitourcountry.（將來）

2.Thisnaughtyboyistostayhereuntilclassisover.(命令）3.Thedriveristoblamefortheaccident.（應該做）

4.Ifyoudon'tstudyhard,youaretobealoser.（注定發(fā)生）

5.Thebooksarenottobetakenoutside.（禁止）4、todo+be+todo平行結構。1.Toseeistobelieve.2.Toliveistolearn,tolearnistobetterlive.3.Toworkistoearnaliving4.Tobekindtotheenemyistobecrueltothepeople.三、動詞不定式作表語和ving作表語的區(qū)別1.動詞不定式和ving作表語時，要注意與句子的主語在形式上保持一致，即若句子的主語為ving，則表語也應使用ving；若主語為動詞不定式，則表語也應使用動詞不定式。Toseeistobelieve.=Seeingisbelieving.動詞不定式和ving作表語時可換用，但以下情況除外:ving表示的動作是較為抽象的、習慣性的、經常發(fā)生的，而動詞不定式通常表示一次性、具體的、將要發(fā)生的動作；eg：Herbestwishistoputhernewideasintopractice.Hisjobistopaintthewallswithintwohours.Hisjobispaintingthewalls.填空練習

1.Themottoofthelittleboywhowassufferingfromaseriousdiseasewas_______(live)everydaymerrily.2.WhatIwouldsuggestis_______(put)offtheoutgoingduetotheterribleweather.3.TheonlythingIcandois_____________(concentrate)onmystudy.

4.Medicalexpertssaythemosteffectivewaytopreventthespreadofdiseaseisforpeople________(wash)theirhandswithsoapandwater.5.Allhewantedafteratiringdaywas_______(leave)alone.6.Thepurposeofthisraceis___________(inspire)usstudentstopaymoreattentiontophysicalexercise.(2020.全國I卷)7.Myaimis________(go)toTsingHuaUniversity.8.Thepresentsituationseems______________(improve)daybyday.9.Yourhardworkis________________(reward)inthefuture.10.Havingatripabroadiscertainlygoodfortheoldcouple,butitremains___________(see)whethertheywillenjoyit.11.Theboywas(blame)forwhathehaddone.12.Oneofthemostdamagingthingsaparentcoulddowas(punish)theirchildrenforpoormarks.13.Whileregularlyeatingoutseemsto(bee)monformanyyoungpeopleinrecentyears，it’snotwithoutacost.14.Anotherwaytohi