Unit+2+Healthy+Lifestyle+Discover+Useful+Structures课件-【知识精研+拓展提升】高中英语人教版（2019）选择性必修第三册+

DiscoverUsefulStructuresUnit02HealthyLifestyle新人教选择性必修三LearningAims

Afterthisperiod,studentswillbeableto:1.Tomasterthedifferentformsanduseoftheinfinitive;2.TounderstandthedifferencesoftheInfinitiveandthegerundassubject;3.TousetheInfinitiveassubjecttodiscusshealthylifestyles.TeachingEmphases&difficulty1.Helpstudentstoexploretheuseoftheinfinitivesassubject;2.Makesurestudentsusetheinfinitivecorrectlyinspecificcontext.Lead-inAnalyzewhatdoestheunderlinedpartserveasineachsentenceandtranslatethemintoChinese.Topreventharmfulhabitslikethesefromdominatingateenager’slifeisessential.(para1)Tochangebadhabit

isnevereasy,evenwithmanyattempts.(para2)改变不良习惯从来都不是一件容易的事情，即使你三番五次地尝试。防止此类有害习惯主宰青少年的生活是至关重要的。系动词表语主语主语系动词表语

todo不定式放在句首作主语useful/turnto/fitnessconsultant/foradviceItisusefultoturntoafitnessconsultantforadvice.illegal/dangerous/take/drugsItisillegalanddangeroustotakedrugs.harmful/often/skip/breakfastItisharmfultooftenskipbreakfast.Lead-inLead-inIttookthesurgeonthreehours

tofinishmymother’slungsurgery.TojointhePeople’sLiberationArmy,itisrequiredformentoshaveofftheirbeards.

Itwasnotpolitetodisturbyourneighbourswithloudmusiclastnight.Readthefollowingsentencesandanalyzewhatdoestheunderlinedpartserveasineachsentence.(activity1)形式主语真正主语形式主语真正主语形式主语真正主语用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。练一练1.Sometimesit’sbetter

（stay)calmwhenintrouble.2.Itwasfoolish

hertomakesuchamistake.3.

Itisrude

himtosaythattoalady.4.Itisdifficult

teenagerstolivealoneinaforeigncountry.tostayofofforThedifferencebetweentheinfinitiveandthegerund

不定式与V-ing作主语的区别不定式作主语表示一次性的、具体的、将来的或未做的动作；动名词作主语表示一般的、抽象的、泛指的或者已经完成的动作。__________(finish)thetaskintimeisagreatchallenge.___________(walk)afterdinnerisgoodtohealth.--WhathasmadeJannysoupset?--_______(lose)twoticketstothecinema._________(get)totheparkbybikewilltakeabout20minutes.TofinishWalkingLosingTogetHow to use the computer is a question.Lead-inWhen to go therehas not been decidedyet.Trytofindthesubjectofeachsentence,andtranslatethemintoChinese.主语主语如何使用电脑是一个问题。还没决定什么时候去那里。疑问词+不定式作主语疑问词+不定式可用于该结构的疑问词疑问代词：who，whom，what，which疑问副词：when，where，how常接该结构的动词：know，see，decide，tell，ask，consider，explain，learn，wonder特殊疑问词+不定式在句中可以作：主语、宾语和表语1._______________theriverisstillaproblem.怎样过桥仍然是个问题。（作主语）2.______________________hasnotbeendecided还没有决定去哪儿露营。（作主语）3.Wehavenowidea__________________________________.我们不知道如何控制水污染。（作宾语）4.Thequestionis________________________.问题是在那里举行这个晚会。（作表语）

HowtocrossWheretogocampinghowtocontrolthewaterpollutionwheretoholdtheparty练一练补全下面句子动词不定式作主语有三种形式：直接放在________作主语；为了保持句子平衡，用________作形式主语，放在句首，把真正的主语—动词不定式置于句后；和_________构成短语作主语。句首it疑问词SummaryLead-inObserveandDiscover1.Toseeisto

believe.2.To

do

this

isto

cut

the

foot

to

fit

the

shoe.3.To

say

isonethingandto

do

isanother.4.To

make

a

detailed

plan

isagoodideatomakeitsuccessful.从位置上看，动词不定式作主语，通常放在句首。当句子主语和表语都是非谓语时，通常要_________，例如：Toseeistobelieve.=Seeingisbelieving.保持一致Observation1ObserveandDiscoverForhimtoadmithismistakesisnoteasy.Forustofinishthecompositioninaquarterofanhourisreallydifficult.

动词不定式作主语可以带上自己的____________，一般用for/of短语来表示。但此时多使用形式主语it来引起，使得句子保持平衡。例如，第2句可以改为：Itisreallydifficultforustofinishthecompositioninaquarterofanhour.逻辑主语Observation2ObserveandDiscoverObservation31.Tobeworkingalldaylongisabore.

2.Tohavemadethesamemistaketwiceisunforgivable.3.Toloveandtobelovedisthegreathappiness.动词不定式作主语可以有不同的_____________形式，例如，____________，_______和_______语态。时态和语态一般进行时完成时被动ObserveandDiscoverObservation41.Itisn’trighttotalklikethat.

2.It’sdifficulttomasterEnglish.3.It’shardformetoanswerthequestion.4.Itisbettertohavelovedandlostthannevertohavelovedatall.以上四个句子有两点共同之处：句子的真正主语都是____________，但都使用it作形式主

语；2.

句子的表语都是________。动词不定式形容词it+be+adj+(逻辑主语)+todosthObserveandDiscoverObservation5Itisn’trightforustostophalfway.

=Tostophalfwayisnotright.2.It’skindofyoutothinksomuchofus.

=Youarekindtothinksomuchofus.动词不定式的逻辑主语常用_____________来表示，当形容词修饰动词不定式时，此时常用介词_____。当表语形容词表示不定式的逻辑主语的性质或特征时，则用介词____。for/of+sbforofObserveandDiscoverObservation61.It’sourduty

todothat.

2.It’samistakenottohelpthem.

3.Itmustbegreatfun

toflytothemooninaspaceship.以上三个句子的表语都是_______，它们可归纳为一个共同句式：_____________________________。

名词

it+be+n+todosthObserveandDiscoverObservation71.Ittookmemorethananhourtodomyhomework

yesterdayevening.2.It

will

takeusalongtimetowalkthere.3.Howlongdoesittaketogetthere?

4.Howmuchdiditcostyoutosendthepackage?以上四个句子是动词不定式作真正主语，由

it作形式主语引导的句子，它们的谓语是_____________。它们的共同句式是_________________________________________________，表示某人花多少时间或金钱做某事。

take/costittakes

(costs)sbsometime

/moneyto do sthObserveandDiscoverObservation8Howtousethecomputerisaquestion.Wheretoputthebikes

isbeingdiscussed.Whenandwheretohavethemeetinghasnotbeendecided._____________构成不定式短语作主语。疑问词包括疑问代词who、whom、what、which、whose以及疑问副词when、where和how。此外连接词whether也适用。此时，疑问词+todo结构可以转化为一个__________，例如：Howtousethecomputerisaquestion.

=___________________________________________疑问词+todo主语从句Howwecanusethecomputerisaquestion.不定式短语作独立成分一些不定式短语可用作独立成分，通常位于句首，有时位于句中或句末，要用逗号同其他句子成分隔开。tobegin/startwith首先tosumup总而言之

toconclude总而言之，最后totellthetruth说实话

tobefrank坦白地说tobehonest说老实话tobebrief简言之

Furtherthinking1.______(do)morningexercisesregularlyisgoodforyourhealth.

2.Itfeelsreallygood______(do)morningexercisestoday.DoingtodoCompletethefollowingsentencesandcomparetheirusages.Conclusion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PracticeandApplyⅢPracticeandApplyJointhewordstomakefullsentences,andthenjointhesentencestomakeaparagraph.(P17activity2)1.important/avoid/passivecigarettesmoking

Itisimportanttoavoidpassivecigarettesmoking.willtake/nutritionspecialist/abalanceddietmenu/make/anhour/foryou________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Itwilltakeanhourforanutritionspecialisttomakeabalanceddietmenuforyou.PracticeandApplyJointhewordstomakefullsentences,andthenjointhesentencestomakeaparagraph.(P17activity2)useful/turnto/fitnessconsultant/foradvice________________________________________________________________________________illegal/dangerous/take/drugs________________________________________________________________________________harmful/skipbreakfast/often________________________________________________________________________________Itisharmfultoskipbreakfast(too)often.Itisusefultoturntoafitnessconsultantforadvice.Itisdangeroustotakeillegaldrugs.PracticeandApply

(P17activity2)Itisimportanttoavoidpassivecigarettesmoking.

Itisusefultoturntoafitnessconsultantforadvice.Itisdangeroustotakeillegaldrugs.Itisharmfultoskipbreakfast(too)often.Itis/was+形容词+(forsb)todosth往往用于表达观点句型分析Itwilltakeanhourforanutritionspecialisttomakeabalanceddietmenuforyou.Ittakes/took/willtakesbsometimetodosth或Itis/wasrequiredforsbtodosth往往用于陈述事实PracticeandApplyTogethealthyandgetridofbadhabits,sometimesitisalsoagoodideatogetprofessionalhelp.Itwilltakeanhourforanutritionspecialisttomakeabalanceddietmenuforyou.Itisalsousefultoturntoafitnessconsultantforadvice.Youcanalsohelpyourselfwithsomecommonsense.Forexample,itisharmfultoskipbreakfasttoooften.Itisimportanttoavoidpassivecigarettesmoking.And,ofcourse,itisdangeroustotakeillegaldrugstoo.Jointhewordstomakefullsentences,andthenjointhesentencestomakeaparagraph.(P17activity2)SampleparagraphPracticeandApplyCompletetheconversationswiththecorrectformsofthephrasesinthebox.(P17activity3)beginwith beincontrolof makeachoicedecideon makeupone’smindA:Hello,doctor.Iwanttoloseweight,butIjustcan’tseemtodoit.Whatcanyoudotohelpme?B:Well,first,it’snecessaryto___________________whatyoueat.Cutoutallfattyfoodandsugarydrinks,andeatmorefruitandvegetables.A:Ireallyneedto_____________awaytoexercisemore.Icoulduseafitnessapp,butmyphone’sfull.B:Sodelete