Non-finiteverbGRAMMARAREVIEW動詞不定式一般由“to+動詞原形”構成，其否定形式是“nottodo”。動詞不定式可以帶賓語或狀語構成動詞不定式短語，沒有人稱和數(shù)的變化，但有時態(tài)和語態(tài)的變化。動詞不定式不能單獨作謂語，可以作主語、賓語、表語、定語、補語等。如：Tofinishthetaskinaweekisveryhard.Thebigboymanagedtopasstheexam.Myworkistocleanthegardeneveryday.ShewasthefirstwomantoswimacrosstheEnglishChannel.Tellhimtocomeherethedayaftertomorrow.主賓表定補Asarealfoodie,Ienjoyallkindsoffoods.Mydreamistotrydifferentrestaurantsandtastevariousfoods.YesterdayIinvitedsomefriendstotryagreatnewrestaurantfordinner.Nothingcanstopourdeterminationtohaveatry.Wedecidedtowaitoutside.Afteranhourofwaiting,wewereinvitedtogointotherestaurantandtaketheorder.Thedishesareextremelydelicious.Itisworthwhiletohavesuchalongwait.Lead-inFindoutto-infinitivesandguesstheirfunctions.表賓主補補01usedassubject1.動詞不定式作主語，表示具體的、一次性的或者表示將來含義的動作，且謂語動詞常用單數(shù)。如：

Tomasteranewskillisnotaneasything.

Toseeistobelieve.

Tohelpothersisourduty.Totalkwithherisagreatpleasure.

01usedassubject

2.動詞不定式短語作主語時，為了保持句子平衡，往往用it作形式主語，而將動詞不定式短語置于句末。如：

ItisimportanttoenlargeEnglishvocabulary.ItwouldbeawasteoftimetolookupeverynewwordwhenyoureadanEnglishnovel.

其常見句型有以下4種：①

It＋is＋名詞＋todosthIt'sourdutytotakegoodcareoftheold.②

Ittakes/tookwilltakesb＋sometime/money＋todosthItwilltakeusthreehourstowalkthere.③

It＋be＋形容詞＋for/ofsb＋todosthIt’sverykindofyoutotelluswhathappenedyesterday.Itisimportantforchildrentotellrightfromwrongatanearlyage.④Itseems(appears)＋形容詞＋todosthItseemedimpossibletofinishtheworkontime.01usedassubject

用it做形式主語改寫下面句子(1)TospeakEnglishwellisn'taneasyjob.

(2)Toimproveourteachingmethodisveryimportant.

(3)Totalkwithherisagreatpleasure.

(4)Tolookupeverynewwordwouldbeawasteoftime.

Itisn’taneasyjobtospeakEnglish.

Itisveryimportanttoimproveourteachingmethod.

Itisagreatpleasuretotalkwithher.

Itwouldbeawasteoftimetolookupeverynewword.01usedassubject

3.“特殊疑問詞+不定式”構成的不定式短語作主語時，且謂語動詞常用單數(shù)。常見的特殊疑問詞有：what,who,which,when,where,why,how等。如：

Wheretoholdthemeetinghasn’tbeendecided.

Howtorelievethepainisaquestion.02usedaspredicative

1.動詞不定式作表語，通常說明主語的具體內(nèi)容。

其主語通常是aim,ambition,dream,duty,goal,idea,intension,plan,purpose,task,way,wish等表示意向、打算、計劃的詞。如：Hisambitionistobecomeanactor.Herdutyistolookafterthechildren.

不定式作表語通?？梢院椭髡Z位置互換。Mydreamistobeadoctor.＝Tobeadoctorismydream.02usedaspredicative

2.某些系動詞，如be（是）、seem（看起來）、appear（看起來）、prove（證明）、turnout（結果）等，后面可以接不定式作表語。其中，除了be動詞之外，seem、appear、prove、turnout后面的表語若是以“tobe+...”的形式出現(xiàn)，通?？梢允÷詔obe。He

seems(tobe)busy.

＝He

appears(tobe)busy.Theplan

proves(tobe)right.

＝Theplan

turnsout(tobe)right.

Attention:

有些系動詞，如sound（聽起來）、smell（聞起來）、taste（嘗起來）、feel（感覺）、become（成為）等，通常不可以接不定式作表語。練習：判斷下列句子正誤Itsmellstobedelicious.Thebookseemsavailable.Thecaketastestobeyummy.

F

T

F02usedaspredicative3.“特殊疑問詞+不定式”通常與be動詞構成系表結構，作be動詞的表語。如：Thequestionishowtocarryouttheplan.4.當主語部分有實義動詞

do

時(以及do的其他形式時),作表語的動詞不定式通常要省略to

(即“前有do,后無to”)。如：Whatyoushoulddois(to)openthedoor.AllIwanttodonowis(to)havearest.

單個不定式(不定式短語)做主語，謂語動詞用單數(shù)Toplaybasketball______(be)great.如果and連接兩個或更多并列的不定式(不定式短語)作主語，謂語動詞就用復數(shù)Toimprovepeople’slifeandtospeedupsocialistconstruction______(be)ourtwoimportanttasks.Whenandwheretodo________________________(notdecide)yet.Whattodoandwheretodo___________________________(notdecide)yet.isarehasn’tbeendecidedhaven’tbeendecided1.It’sbadforyoureyes________(play)computergamestoomuch.2.Hisambitionis_____________(become)asuccessfulscientistwhenhegraduates.3.___________(enjoy)theconvenienceofdigitalpayment,manyseniorcitizensstartedtousesmartphones.4.Whatwecandois____________(ensure)thatallstudentshaveaccesstoahealthydiet.5.It’sreallykindofhim________(let)ususehisswimmingpool.toplaytobecomeToenjoy(to)ensuretoletPracticeBApplyingtherulesDearTom,IamwritingtothankyoufortakingmetoSkyBuffet.Itwassokindofyoutoinvitemeandbookatablebythewindow.Itwaswonderfultoseethecitysceneryandwatchthebeautifulsunset.IhavealwayswantedtogiveSkyBuffetatry,andit