高考英语二轮复习不定式做主语课件25张

选择性必修三Unit2todousedasSubjec1.Studentscanunderstandthemeaningandfunctionoftodousedassubject;2.Studentscanmasterthesentencestructureofitastheformalsubject,andtodoisthetruesubject;3.Studentscantellthedifferencebetweentodousedassubjectanddoingusedassubject;3.Studentscanapplywhattheyhavelearnedintopractice;Teachingobjectives

1._______(prevent)harmfulhabitslikethesefromdominatingateenager'slifeisessential.2.________(change)badhabitsisnevereasy,evenwithmanyattempts.3.Afterall,itisnoteasy_______(break)badhabits.4.However,duringthisperiod,itcanbeeasyforsomeofthem_______(form)badhabits.Readthefollowingsentences

1.Topreventharmfulhabitslikethesefromdominatingateenager'slifeisessential.2.Tochangebadhabitsisnevereasy,evenwithmanyattempts.3.Afterall,itisnoteasytobreakbadhabits.4.However,duringthisperiod,itcanbeeasyforsomeofthemtoformbadhabits.

todo作主语与it作形式主语之间的转换

Itwilltakethenutritionspecialistanhourtomakeabalanceddietmenu

foryou.Itisusefultoturntothefitnessconsultantforadvice.Itisillegalanddangeroustotakedrugs.Itisoftenharmfultoskipbreakfast.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.Howtobreakthebadhabitisthequestion.Wheretogohasn'tbeendiscussed.IthasnotbeendecidedwhethertoflytoParis.

”疑问词+todo”作主语

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。doingtodo(somethingyouhavealreadydone)Doing...ismyfavoriteactivityDoing...oftenhelpsme...(somethingyouwanttodo)Todo...isessentialforus.Todo...canhelpme...eatfruitsandvegetablesdrink8glassesofwateradaywashhandsbeforemealshaveenoughsleepwalkaftermealstakeregularexercise一【含义】

一般表示具体的或某一次的或将来的动作。二【位置】

1.Topreventharmfulhabitslikethesefromdominatingateenager'slifeisessential.2.Tochangebadhabitsisnevereasy,evenwithmanyattempts.3.Afterall,itisnoteasytobreakbadhabits.4.However,duringthisperiod,itcanbeeasyforsomeofthemtoformbadhabits.

句首it作形式主语,不定式放句尾考点一：不定式作主语时的主谓一致原则

单个不定式作主语，谓语动词用_______两个或两个以上的不定式作主语，若语意一致或作为一个整体，谓语动词用_________两个或两个以上的不定式作主语，若语意不一致，谓语动词用________单数单数复数ToimproveEnglish_____themosturgentthingformenow.Toloveandtobeloved_____________issweettous.Tobuildupourphysicalandmentalhealthandstimulateourinterestinlearning_______(be)twoessentialtasks.

Exercises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.

总结一般规律：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;

Exercises2.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.Ittookmemorethananhourtodomyhomeworkyesterdayevening.拓展1：it作形式主语,doing作真正的主语1.浪费时间做某事:Itisawasteoftimedoingsth2.做某事是没有用的It'snouse/nogooddoingsthIt'suselessdoingsthItisfun/nofundoingsth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)todo作主语todo作主语位于句首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

Summary

总结1.Itis+adj.+(forsb)todoItiseasyformetolearnhowtodrive.2.Itis+adj.+(ofsb)todoItiscleverofyoutoapplyfortheposition.Mattersnee