【课件】Unit 2 Discover useful structrues语法精讲课件-高中英语人教版（2019）选择性必修第三册

语法精讲Unit2

TheInfinitive

(todo……)不定式的时态和语态不定式主动被动

一般towritetobewritten

进行tobewriting

完成tohavewrittentohavebeenwritten

完成进行tohavebeenwriting

4.Itisimportant

______Tomtogetthatjob.Itiskind______youtohelpmewithmyhomework.

1.______(talk)withhimisagreatpleasure.2.______(help)othersisourduty.TotalkTohelpItisourdutytohelpothersforof3.Itiseasy______________________(学生读)forthestudentstoread.Lookatthefollowingsentencesandpayattentiontotheitalicisedinfinitives.Findmoreinfinitivesinthereadingpassage.Inpairs,discusstheirmeaningsandfunctions.1Tochangebadhabitsisnevereasy.2Ittookthesurgeon(n.外科医生)threehourstofinishmymother’slungsurgery(n.外科手术).主语主语3TojointhePeople’sLiberation(n.解放)Army,itisrequiredformentoshaveoff(剃掉,刮掉)theirbeards.4Itwasnotpolitetodisturb(v.打扰)yourneighbourswithloudmusiclastnight.目的状语主语主语Moresentencesinthereadingpassage:1.However,duringthisperiod,itcanbeeasyforsomeofthemtoformbadhabits.2.Topreventharmfulhabitslikethesefromdominatingateenager’slifeisessential.3.Tochangebadhabitsisnevereasy,evenwithmanyattempts.4.Afterall,itisnoteasytobreakbadhabits.动词不定式作主语常见的三种形式1.不定式作主语通常位于句首，表示具体的某次动作，谓语动词用单数。e.g.Toseeistobelieve.百闻不如一见。Togetupearlyisnecessary.早起是必要的。Tolearnaskillisveryimportantforeveryoneinsociety. 学习一项技能对社会上的每个人都很重要。Tofinishthebuildinginamonthisdifficult.要在一个月内完成这座建筑是困难的。2.动词不定式与疑问词who,whom,whose,what,which,when,

where,how等连用构成不定式短语，也可作主语。

e.g.Howtousethecomputeristhequestion.如何使用计算机是个问题。Wheretogohasnotbeendecided.去哪儿还没有定下来。3.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。e.g.It’snoteasytoworkouttheproblem.=Toworkouttheproblemisnoteasy.计算出这道题不容易。Itisinterestingtoplaywithsnowinwinter.冬季里玩雪是很有趣的。Itisterribletoseetheshipsinkingintothesea.目睹轮船沉入大海，真是太可怕了。it作形式主语代替真正主语不定式常见于以下情况中：Itis+adj.+for/ofsb.todosth.Itis+n.+(forsb.)todosth.Ittakes/took/willtakesb.sometime/moneytodosth.【温馨提示】常用于表示事物的特征，用于此句型的形容词有：easy, hard, difficult, possible, important, impossible, necessary, good, bad, exciting, interesting, surprising等。1)Itis＋adj.

＋forsb.todosth.sb.是todosth.的逻辑主语Itis+adj.+for/ofsb.todosth.e.g.Itisnecessaryforyoungstudentstolearna foreignlanguage.对年轻的学生来说，学习一门外语是必要的。Itisnecessaryforyoutochangeyourjob.你有必要换工作。Itwasimpossibleforthemtocompletethetaskinsuchashorttime.他们不可能在这么短的时间内完成这项任务。It’simportantforustokeepthewaterclean.保持水质清洁对我们来说是很重要的。常见的此类形容词有：

kind, nice, wise, silly, polite, impolite, friendly, foolish, clever等。2)Itis＋adj.＋ofsb.＋todosth.形容词用来表示不定式的逻辑主语(sb.)的性质、特征或品德e.g.Itwassillyofyoutogiveupsuchagoodchance！

你放弃这么好的一个机会，真傻!It’sverykindofyoutosayso.你这样说真是太好了。Itisfriendlyofthefamilytotrytomakemefeel

athomeintheirhouse.这家人对我很友好，使我在他们家里感到宾至如归。Itwasrudeoftheboytojumpthequeue! 那个男孩插队真是太无礼了!常见的名词有：pity, shame, pleasure, one’sduty, one’sjob, fun, joy, goodmanners, badmanners等。Itis+n.+(forsb.)todosth.e.g.Whatapityitisforyoutohavemissedsuchawonderfulfilm.真遗憾你错过了这样一个精彩的电影。  Itmustbegreatfuntoflytothemooninaspaceship.

乘宇宙飞船飞往月球一定很有趣。Ittakes/took/willtake

sb.sometime/money

todosth.做某事花费某人多长时间(钱)e.g.Ittookmemorethananhourtodomyhomeworkyesterdayevening.昨天晚上我做作业用了一个多小时。Itwilltakeusalotofmoneytobuythathouse.买那套房子要花费我们很多钱。3.如果要说明不定式表示的动作是谁做的，可以在不定式前加一个由for/of引起的短语,构成__________。2.不定式作主语时,可以用it作_______________.Itis+adj+forsbtodo……5.Itis+adj+ofsbtodo………(adj:kind,good,nice,wise,unwise,clever,silly,stupid,foolish,careless,rude,polite,naughty)（修饰人品形容词）（修饰物的形容词）1.单个不定式作主语，谓语动词_________单数形式主语不定式的复合结构语法总结(adj.:easy,difficult,comfortable,pleasant,light,dangerous，tiresome,interesting,heavy,fit)Jointhewordstomakefullsentences,andthenjointhesentencestomakeaparagraph.Youcanaddyourownsentencesifnecessarytomakeyourparagraphmoremeaningful.1.important/avoid/passivecigarettesmoking

Itisimportanttoavoidpassivecigarettesmoking.n.香烟2.willtake/nutritionspecialist/abalanceddietmenu/make/anhour/foryouItwilltakethenutritionspecialistanhourtomakeabalanceddietforyou.3.useful/turnto/fitnessconsultant/foradviceItisusefultoturntothefitnessconsultantforadvice.n.专家n.顾问4.illegal/dangerous/takedrugs5.harmful/skipbreakfast/oftenItisillegalanddangeroustotakedrugs.Itisharmfultoskipbreakfastoften.n.毒品，药品v.跳过Completetheconversationswiththecorrectformsofthephrasesinthebox.1.A:Hello,doctor.Iwanttoloseweight,butIjustcan’tseemtodoit.Whatcanyoudotohelpme?B:Well,first,it’snecessaryto________________whatyoueat.Cutoutallfattyfoodandsugarydrinks,andeatmorefruitandvegetables.beincontrolofbeginwith,beincontrolof,makeachoice,decideon,makeupone’smind2.A:Ireallyneedto____________awaytoexercisemore.Icoulduseafitnessapp,butmyphone’sfull.B:Sodeleteafewfiles.I’msuretheappdoesn’ttakeupmuch