Unit2HealthyLifestyleDiscoverusefulstructures不定式做主语语法课件高中英语人教版选择性

DiscoveringUsefulStructures新人教选择性必修三Unit2HealthyLifestyleInfinitivesasSubject不定式作主语.✎

Learningobjectives

✎toidentifyandsummarize“todo”structureasthesubject;toapply“todo”structureasthesubjectproperlytorealsituations.DiscoverUsefulStructuresLead-inHowever,duringthisperiod,itcanbeeasyforsomeofthem________badhabits.【教材回顾】1.However,duringthisperiod,itcanbeeasyforsomeofthem________(form)badhabits.2._________

(prevent)harmfulhabitslikethesefromdominatingateenager’slifeis

essential.3._________(change)badhabitsisnevereasy,evenwithmanyattempts.4.__________(facilitate)apositivechangeinourbadhabits,wemustfirstexamineourbadhabitcyclesandthentrytoadaptthem.5.whenwecometoanescalator(cue),ournormalroutineis_______(ride)it,butwecouldchangethisroutineintosomethingmorepositivebytakingthestairsinstead.6.Infact,themostsuccessfulway_________(change)isnotsuddenly,butoveraperiodoftime.7._________(reach)thegoalofchange,apersonmustshowsomedisciplineandrepeatedlytakemanysmallsteps.8.Afterall,itisnoteasy_______(break)badhabits.toformTofacilitatetoridetochangetobreakTochangeTopreventToreachHowever,duringthisperiod,itcanbeeasyforsomeofthem________badhabits.1.However,duringthisperiod,itcanbeeasyforsomeofthem________(form)badhabits.2._________

(prevent)harmfulhabitslikethesefromdominatingateenager’slifeisessential.3._________(change)badhabitsisnevereasy,evenwithmanyattempts.4.__________(facilitate)apositivechangeinourbadhabits,wemustfirstexamineourbadhabitcyclesandthentrytoadaptthem.toformTofacilitateTopreventTochangePayattentiontothereditalicizedinfinitivesanddiscussthemeaningsandfunctionsoftheitalicisedinfinitives.主语主语主语目的状语✎

探索发现

✎However,duringthisperiod,itcanbeeasyforsomeofthem________badhabits.5.whenwecometoanescalator(cue),ournormalroutineis_______(ride)it,butwecouldchangethisroutineintosomethingmorepositivebytakingthestairsinstead.6.Infact,themostsuccessfulway_________(change)isnotsuddenly,butoveraperiodoftime.7._________(reach)thegoalofchange,apersonmustshowsomedisciplineandrepeatedlytakemanysmallsteps.8.Afterall,itisnoteasy_______(break)badhabits.toridetochangetobreakToreach表语后置定语目的状语主语✎

探索发现

✎主语InfinitivesasSubject不定式作主语2._________

(prevent)harmfulhabitslikethesefromdominatingateenager’slife

is

essential.3._________(change)badhabitsisnevereasy,evenwithmanyattempts.1.However,duringthisperiod,itcanbeeasyforsomeofthem________badhabits.8.Afterall,itisnoteasy_______(break)badhabits.TopreventTochangetoformtobreak系动词表语

todo不定式放在句首作主语主语系动词表语真正主语形式主语系动词表语形式主语系动词表语真正主语用it作形式主语，放在句首，把真正的主语

—动词不定式置于句后。✎

探索发现

✎Tosee_____(be)tobelieve.Togetgood_______(require)alotofhardwork.Tolearnaskill_____(be)veryimportantforeveryoneinsociety.Tochangebadhabits

_____(be)nevereasy,evenwithmanyattempts.

isisisrequires✎

Exercise✎用所给词的适当形式填空并翻译句子。✎

Exploregrammar

✎动词不定式作主语主谓一致总结：①动词不定式作主语时，通常位于句首，表示具体的某次动作，谓语动词常用__________。单数✎

Exploregrammar

✎动词不定式作主语主谓一致1.做喜欢的事，见想见的友乃人生最快乐的事Todowhatyouloveandtomeetthefriendsyouwanttoseearethehappiestthingsinlife.2.爱与被爱

是人所能得到的最大幸福。Toloveandtobeloved

isthegreatesthappinessonecanget.总结：②两个及以上动词不定式作主语，谓语动词用复数形式。总结：③两个并列的不定式语义基本一致，谓语动词用单数形式。直接置于句首（较正式/强调），通常用于不定式短语较短，或为了强调动作本身时。✎

Exploregrammar

✎一、动词不定式直接作主语，放在句首1.喝桂花茶有益身体

Todrinkosmanthusteabenefitsthebody.2.沿石桥散步令人放松Towalkalongthestonebridgeisrelaxing.3.采摘鲜花是不被允许的

Topickfreshflowersisnotallowed.不定式作主语基本用法：总结：动词不定式直接置于句首（较正式/强调），通常用于不定式短语较短，或为了强调动作本身时。核心结构：To+动词原形+谓语（单数）+其他成分常置于句末✎

Exploregrammar

✎二、动词不定式作主语，常置于句末不定式作主语基本用法：总结：当主语较长，谓语较短时，常用it作形式主语放在句首，而将真正的主语—不定式放到谓语的后面。

标准句型结构：Itis+形容词/名词+todosth.

1.这家人对我很友好，使我在他们家里感到宾至如归Itisfriendlyofthefamilytomakemefeelathomeintheirhouse.

2.代表我的学校发表演讲是我的荣幸。Itisanhonourtogiveaspeechonbehalfofmyschool.3.外科医生花了三个小时才完成手术。Ittookthesurgeonthreehours

tofinishtheoperation.Itisyourfaultnottogetthereintime!todo作主语，位于句末。Ittakesusanhour

(get)therebybus.It’sourduty

(help)thepoor.Itisagreatenjoyment

(spend)ourholidayinthemountains.It+takes/took/willtake(sb.)+时间(金钱)+todosth句型1句型2Itis+名词+todosth.togettohelptospend常见的名词有：pity,shame,pleasure,one’sduty,one’sjob,fun,joy,goodmanners,badmanners等✎

Exploregrammar

✎不定式作主语，置于句末的基本用法：✎

Exercise✎Itwilltakehalfanhour________(send)hertoherdestination.Itwilltakeanutritionspecialistanhour_________(make)abalanceddietmenuforyou.Asachef,_______wasmydutytocook.Itisapity_______(miss)thechancetoseeyourshow.______tookmemorethananhourtodomyhomeworkyesterdayevening.tomakeittomiss用所给词的适当形式填空并翻译句子。IttosendItiseasyformetofinishthisworkbeforeten.Itis+形容词+forsb.+todosth.句型3Itis+形容词+ofsb.+todosth.句型4Itisverykindofyoutogivemesomehelp.✎

Exploregrammar

✎不定式作主语，置于句首的基本用法：若adj.

“描述人的品格、特点”，用of，如kind,

nice,

wise,

silly,

polite,

impolite,

friendly,

foolish,

clever;若adj.“描述事或行为的特征”，用for，如easy,

hard,

difficult,

possible,

important,

impossible,

necessary,

good,

bad, exciting,

interesting,

surprisingIt+谓语动词+todo+其他.其它✎

Exploregrammar

✎不定式作主语，置于句首的基本用法：Itmatterstodosth做某事很重要Ithappens

todosth碰巧做某事Itseemstodosth似乎要做某事1.Itmatterstofollowtheemperor'sorder.遵从皇上旨意至关重要2.Ithappens

tomeetmyoldfriendintheroad.恰巧在路上遇见了我的老朋友。3.Itseemstoraininthecity.这个城市好像要下雨了。✎

Summary

✎Itisnecessary______youngstudentstolearnaforeignlanguage.Itwassilly______youtogiveupsuchagoodchance!

Itisimportant_______ustoexpressouropinions.Itwasnotpolite______youtodisturb

yourneighbourswithloudmusiclastnight.Itisnecessaryforyou________(change)yourjob.Showtimeforofoffortochangeit作形式主语的常见句型Itis+形容词（+forsb.）+todosth.Itiseasyformetolearnhowtodrive.Itis+形容词（+ofsb.）+todosth.Itiscleverofhimtoleavethatcompany.③Ittakes/tooksb.+sometime+todosth.

Ittakesmeanhourtodohomeworkeveryday.④Itis+名词（apleasure/apity/anhonor...）+todosth.

It’sourdutytotakecareoftheold.✎

Summary✎It+谓语动词+todo+其他.动词不定式与疑问词连用构成不定式短语作主语。Wheretotravelisunsure.Whethertohaveahollidayisundecided.总结：特殊疑问词who,whom,whose,what,which,when,where,how+不定式短语做主语。或者连词whether+

不定式短语做主语

✎

Exploregrammar

✎三、“疑问词+动词不定式”作主语✎

Exercise✎1.When________(start)hasnotbeendecidedyet.2.How________(use)thecomputeristhequestion.3.Where________(go)

hasnotbeendecided.【应用实践】根据汉语句意完成英语句子。①何时离开还没有决定。________________hasnotbeendecided.②如何开始比到哪里停止还困难。____

__________

ismoredifficultthan________________.用所给词的适当形式填空并翻译句子。tostarttousetogoWhen

to

leaveHow

to

beginwhereto

stopTolook

afterchildrenisherjobtoday.她今天的工作是看孩子。Lookingafterchildrenisherwork.她的工作是照顾孩子。[Summary]不定式作主语和动词-ing形式作主语的区别：动名词作主语表示_______________的行为；不定式作主语表示_________________________

动作。经常性或习惯性具体的、一次性的或将来的1.______(do)morningexercisesregularlyisgoodforyourhealth.

2.Itfeelsreallygood______(do)morningexercisestoday.Doingtodo✎

难点突破

✎✎

Exercise

✎1.Ittookyearsofwork___________(reduce)theindustrialpollutionandcleanthewater.2.__________(walk)isagoodformofexerciseforboththeyoungandtheold.3.Todothis_____(be)tocutthefeettofittheshoes.4._____isdifficultforhimtoadmithismistakes.5.Itwasselfish_____himnottosharehisdictionarywithothers.toreduceWalkingisItof✎

Exercise

✎一、连词成句(Page17)1.important/avoid

/passivecigarette(香烟)smoking____________________________________________________________2.willtake/nutritionspecialist(营养专家)/abalanceddietmenu/make/anhour/

foryou____________________________________________________________

3.useful/turnto/fitnessconsultant(健身顾问)/foradvice____________________________________________________________4.illegal/dangerous/take/drugs____________________________________________________________5.harmful/skip（跳过）breakfast/often____________________________________________________________Itwilltakenutritionspecialistanhourtomakeabalanceddietmenuforyou.Itisusefultoturntofitnessconsultantforadvice.Itisillegalanddangeroustotakedrugs.Itisharmfultoskipbreakfastoften.Itisimportanttoavoidpassivecigarettesmoking.毒品/药物二、Completetheconversationswiththecorrectformsofthephrasesinthebox.1.A:Hello,doctor.Iwanttoloseweight(减肥),butIjustcan’tseemtodoit.Whatcanyoudotohelpme?B:Well,first,it’snecessaryto________________whatyoueat.Cutout(停止；切断)allfattyfoodandsugary(含糖的)drinks,andeatmorefruitandvegetables.beincontrolofbeginwith,beincontrolof,makeachoice, decideon,makeupone’smind首先控制；掌控做出选择下定决心选定2.A:Ireallyneedto____________awaytoexercisemore.Icoulduseafitnessapp,butmyphone’sfull.B:Sodeleteafewfiles.I’msuretheappdoesn’ttakeup(占据)muchspace.3.A:Beforeexercising,alwaysdoafewwarm-ups(热身活动)to___________.B:Iknow.ButthenIalwaysfeeltootiredtocontinue!beginwith,beincontrolof,makeachoice, decideon,makeupone’sminddecideonbeginwith二、Completetheconversationswiththecorrectformsofthephrasesinthebox.beginwith,beincontrolof,makeachoice, decideon,makeupone’smind4.A:ShouldIgoforthepizzaorthefriedchicken?Ihate_________________likethese.Youknowwhat—I’mgoingtoeatboth!B:Wow!Don’teattoomuchjunkfood—you’llgetfat,I’veactually__________________togoonadiet(节食),soI’lljuststickto(坚持)thefruitsalad.makingchoicesmadeupmymind二、Completetheconversationswiththecorrectformsofthephrasesinthebox.1.Ittakesushours__________________everyday.

我们每天要花上数小时做家庭作业。2.__________________willtakealongtime.要完成这项任务将要花费很长时间。3.__________________inonedayisimpossible.在一天内完成这项工作是不可能的。4._____________________aforeignlanguagewell.要把一门外语学好不容易。5.It’sveryinteresting_________________.踢足球很有趣。6.Fathercriticizedmeandtoldmeit’swrong_______________________.父亲批评了我并且告诉我捉弄别人是错误的。toplayfootballtoplaytricksonotherpeople✎

Exercise

✎todoourhomeworkTofinishthetaskTofinishthisjobIt’snot