人教版（2019）选择性必修第三册Unit 2 Health lifestyle Healthy lifestyle Discover useful structures 课件

UNIT2HEALTHYLIFESTYLEInfinitivesasthesubject

Discoverusefulstructures1.However,duringthisperiod,itcanbeeasyforsomeofthemtoformbadhabits.2.Topreventharmfulhabitslikethesefromdominatingateenager’slifeisessential.3.Tochangebadhabitsisnevereasy,evenwithmanyattempts.4.Afterall,itisnoteasyto

breakbadhabits.5.Whentoholdthesportsmeetinghasnotbeendecided.ObserveandDiscoverLookatthefollowingsentencesandpayattentiontotheinfinitives.P36【语法感悟】①在句1、4中，it是

，代替后面的动词不定式短语。

②在句2、3中，Toprevent...和Tochange...都是动词不定式短语作

________。

③在句5中，Whentohold...是“疑问词+todo”结构，该部分在句中作

。

形式主语

主语

主语

e7d195523061f1c0f0ec610a92cff745ee13794c7b8d98f8E73673273C9E8BE17CC3D63B9B1D6426C348A354AD505654C28F453CD7C8F90EADD06C08281DAED7140E5AAAED5880ECE414DFB6A93B82BE019406867034C3A8500A4827DCF3FBF74A471B736410707E336A01C9ADC9BE02ACCB8DF2121D81636A067B8AE80C6AB6F014154F4E7B7247

总结

思考

位置

含义

本质

名词词性

不定式短语在句中做主语。一【含义】

不定式作主语一般表示具体的或某一次的或将来的动作,谓语动词用单数。To

knowsomethingaboutEnglishisonething;to

knowEnglishisquiteanother.懂一点英语是一回事；掌握英语完全是另一回事。注：单个不定式作主语时，谓语用单数形式；两个及以上不定式作主语时，谓语用复数形式；但作为一个整体时，谓语用单数形式。Wheretogoonaholidayandwhentogofortheholiday_____(have)notbeendecided.Whereandwhentogoonaholiday______(have)notbeendecided.havehas不定式作主语，有时根据表达的需要，可以在添加疑问代词或副词，疑问代词：who，whom，what，which疑问副词：when，where，howwhetherE.g.Howtobreakthebadhabit

isthequestion.Wheretogo

hasn'tbeendiscussed.It

hasnotbeendecided

whethertoflytoParis.

”疑问词+todo”作主语【Practice】Usethecorrectformsofthewordstofillintheblanks.When________(start)hasnotbeendecidedyet.How________(use)thecomputeristhequestion.Ithasbeendecidedwhere________(spend)ourwinterholiday.tostarttousetospend二【位置】1.Topreventharmfulhabitslikethesefromdominatingateenager'slife

isessential.2.Tochangebadhabits

isnevereasy,evenwithmanyattempts.3.Afterall,itisnoteasytobreakbadhabits.4.However,duringthisperiod,it

canbeeasyforsomeofthemtoformbadhabits.

句首it作形式主语,不定式放句尾考点二：it作形式主语常见的句型1.Itis+形容词+for/ofsb+todosthE.g.Itiseasyformetolearnhowtodrive.Itiscleverof

youtoapplyfortheposition.一般规律：若形容词”描述人的属性，特征”,用of;若形容词“描述事或物的特征”,

用for;2.Itis+名词(apleasure/apity/anhonour...)(forsb)+todosthE.g.Itisanhonourtogiveaspeechinbehalfofmyschool.Itisapitytomissthechancetoseeyourshow.3.It

takes/took/willtakesb.sometime/moneytodo

做某事花费,某人多长时间(钱)E.g.Ittookmemorethananhourtodo

myhomeworkyesterdayevening.⁠

⁠完成句子①Itseemedselfishofhim

nottogivehisemployeesanything

⁠.

他不给员工任何东西，这显得他太自私了。②Itseemsapity

torefusetheinvitation

⁠.

拒绝这份邀请似乎是遗憾的。③It’sunwise

ofthemtoturndowntheproposal

⁠.

他们拒绝（采纳）这个建议是不明智的。④Itwillbeamistake

forusnottohelpthem

⁠.

我们不帮助他们将是错误的。nottogivehisemployeesanything

torefusetheinvitation

ofthemtoturndowntheproposal

forusnottohelpthem

Itwilltake

thenutritionspecialistanhourtomake

abalanceddietmenu

foryou.Itisusefultoturn

tothefitnessconsultantforadvice.Itisillegalanddangerousto

takedrugs.Itisoftenharmfulto

skipbreakfast.拓展1：it作形式主语,doing作真正的主语1.浪费时间做某事:2.做某事是没有用的：

3.做某事是没有乐趣的：

4.做某事是没有好处的：Itisawasteoftime

doingsthIt'snouse

doingsthItisnofun/pleasure

doingsthItisnogood

doingsth拓展2：todo和doing作主语的区别Tolookafterchildrenisherjobtoday.

她今天的工作是看孩子。Lookingafterchildrenisherwork.

她的工作是照顾孩子。区别todo通常表示一个将来的、具体的内容;

(动作)doing而则表示一种经常性的、习惯的或抽象的概念。(事情)⁠

⁠单句语法填空①

Tohear

⁠

（hear）yourvoiceissonice.

②

Tolook

⁠

（look）afterthesafetyofthecommunityishisresponsibility.

③

Smoking

⁠

（smoke）isprohibitedhere.④How

tocure

⁠

（cure）thiskindofillnessisstillunknown.

Tohear

Tolook

Smoking

tocure

beincontrolofdecideonbeginwithmakingchoicesmadeupmymindHowcanweloseweight?todo作主语todo作主语位于句首,谓语动词用单数it作形式主语疑问词+todo构成不定式短语和-ing作主语的区别Toreadwithoutreflectingislikeeatingwithoutdigesting.Ittakessb.time/moneytodosth.Itis+adj.+(for/ofsb.)todosth.Itis+n.+(forsb.)todosth.todo表示具体的，将来的动作-ing表示一般的，已经完成的动作与疑问词who,whom,whose,what,which,when,where,how等连用

Summary1A:I'mthinkingaboutridingamotorbiketoschool.Whatdoyouthink?B:Oh?Well,Ithinkit'snecessary________________________________first.2A:Howcomeyoufaintedsuddenlyyesterday?Didn'tyoueatanythinginthemorning?B:I'monadiet.A:That'ssobad!Youknowit'simportant_____________________everymorning.3A:IoftenseeyouaroundCentralPark.B:Yes,Ilike_______________________thereeveryweekend.Weusuallyplayballgames.4A:Ihearthatthenewheadmasterhastoomanythingstodo.B:Yes.Itwillbeabigchallengeforhim_____________________________________.Agroupofstudentsarechattingafterclass.Completetheconversationswiththecorrectformsofthephrasesinthebox.eatagoodbreakfastgetyourparents’permissionhangoutwithfriendsbalanceworkandpersonallife

togetyourparents’permissiontoeatagoodbreakfasthangingoutwithfriendstobalance（his）workandpersonallife(WORKBOOKP69EX.1)Itwilltakeusabouthalfanhour________________（到达）theWestLake.Inthemorning,wewillvisittheplacesofinterestaroundorneartheWestLake,includingthelake,GuHill,Lingyin