選擇性必修三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作主語(yǔ)與it作形式主語(yǔ)之間的轉(zhuǎn)換

Itwilltakethenutritionspecialistanhourtomakeabalanceddietmenu

foryou.Itisusefultoturntothefitnessconsultantforadvice.Itisillegalanddangeroustotakedrugs.Itisoftenharmfultoskipbreakfast.不定式作主語(yǔ)，有時(shí)根據(jù)表達(dá)的需要，可以在添加疑問(wèn)代詞或副詞，疑問(wèn)代詞：who，whom，what，which疑問(wèn)副詞：when，where，howwhetherE.g.Howtobreakthebadhabitisthequestion.Wheretogohasn'tbeendiscussed.IthasnotbeendecidedwhethertoflytoParis.

”疑問(wèn)詞+todo”作主語(yǔ)

總結(jié)

思考

位置

含義

本質(zhì)

名詞詞性

不定式短語(yǔ)在句中做主語(yǔ)。doingtodo(somethingyouhavealreadydone)Doing...ismyfavoriteactivityDoing...oftenhelpsme...(somethingyouwanttodo)Todo...isessentialforus.Todo...canhelpme...eatfruitsandvegetablesdrink8glassesofwateradaywashhandsbeforemealshaveenoughsleepwalkaftermealstakeregularexercise一【含義】

一般表示具體的或某一次的或?qū)?lái)的動(dòng)作。二【位置】

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

句首it作形式主語(yǔ),不定式放句尾考點(diǎn)一：不定式作主語(yǔ)時(shí)的主謂一致原則

單個(gè)不定式作主語(yǔ)，謂語(yǔ)動(dòng)詞用_______兩個(gè)或兩個(gè)以上的不定式作主語(yǔ)，若語(yǔ)意一致或作為一個(gè)整體，謂語(yǔ)動(dòng)詞用_________兩個(gè)或兩個(gè)以上的不定式作主語(yǔ)，若語(yǔ)意不一致，謂語(yǔ)動(dòng)詞用________單數(shù)單數(shù)復(fù)數(shù)ToimproveEnglish_____themosturgentthingformenow.Toloveandtobeloved_____________issweettous.Tobuildupourphysicalandmentalhealthandstimulateourinterestinlearning_______(be)twoessentialtasks.

Exercises考點(diǎn)二：it作形式主語(yǔ)常見(jiàn)的句型1.Itis+形容詞+for/ofsb+todosthE.g.Itiseasyformetolearnhowtodrive.Itiscleverof

youtoapplyfortheposition.

總結(jié)一般規(guī)律：若形容詞”描述人的屬性，特征”,用of;若形容詞“描述事或物的特征”,

用for;

Exercises2.Itis+名詞(apleasure/apity/anhonour...)(forsb)+todosthE.g.Itisanhonourtogiveaspeechinbehalfofmyschool.Itisapitytomissthechancetoseeyourshow.3.It

takes/took/willtakesb.sometime/moneytodo

做某事花費(fèi),某人多長(zhǎng)時(shí)間(錢(qián))E.g.Ittookmemorethananhourtodomyhomeworkyesterdayevening.拓展1：it作形式主語(yǔ),doing作真正的主語(yǔ)1.浪費(fèi)時(shí)間做某事:Itisawasteoftimedoingsth2.做某事是沒(méi)有用的It'snouse/nogooddoingsthIt'suselessdoingsthItisfun/nofundoingsth拓展2：todo和doing作主語(yǔ)的區(qū)別Tolookafterchildrenisherjobtoday.

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

她的工作是照顧孩子。區(qū)別todo通常表示一個(gè)將來(lái)的、具體的內(nèi)容;

(動(dòng)作)doing而則表示一種經(jīng)常性的、習(xí)慣的或抽象的概念。(事情)todo作主語(yǔ)todo作主語(yǔ)位于句首it作形式主語(yǔ)疑問(wèn)詞+todo構(gòu)成不定式短語(yǔ)和-ing作主語(yǔ)的區(qū)別Toreadwithoutreflectingislikeeatingwithoutdigesting.Ittakessb.time/moneytodosth.Itis+adj.+(for/ofsb.)todosth.Itis+n.+(forsb.)todosth.todo表示具體的，將來(lái)的動(dòng)作-ing表示一般的，已經(jīng)完成的動(dòng)作與疑問(wèn)詞who,whom,whose,what,which,when,where,how等連用

Summary

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