Unit 2 Discover useful structures -ppt课件--(2022)高中英语新人教版选择性必修第三册.pptx

1、To learn infinitives used as subjectsTo use infinitives to complete the exercises to do和doing作主语的区别Look at the following sentences and pay attention to the italicised infinitives.Find more infinitives in the reading passage.In pairs,discuss their meanings and functions.1 To change bad habits is neve

2、r easy.2 It took the surgeon(n.外科医生外科医生)three hours to finish my mothers lung surgery(n.外科手术外科手术).主语主语主语主语3 To join the Peoples Liberation(n.解放解放)Army,it is required for men to shave off(剃掉剃掉,刮掉刮掉)their beards.4 It was not polite to disturb(v.打扰打扰)your neighbours with loud music last night.主语主语主语主语目

3、的状语目的状语More sentences in the reading passage:l However,during this period,it can be easy for some of them to form bad habits.l To prevent harmful habits like these from dominating a teenagers life is essential.l To change bad habits is never easy,even with many attempts.l After all,it is not easy to

4、 break bad habits.主语主语主语主语主语主语主语主语 动词不定式作主语常见的三种形式动词不定式作主语常见的三种形式1.不定式作主语不定式作主语通常通常位于句首位于句首，表示具体的某次动作，表示具体的某次动作，谓谓语动词用单数语动词用单数。e.g.To see is to believe.百闻不如一见。百闻不如一见。To get up early is necessary.早起是必要的。早起是必要的。To learn a skill is very important for everyone in society.学习一项技能对社会上的每个人都很重要。学习一项技能对社会上的每个

5、人都很重要。To finish the building in a month is difficult.要在一个月内完成这座建筑是困难的。要在一个月内完成这座建筑是困难的。2.动词不定式与动词不定式与疑问词疑问词who,whom,whose,what,which,when,where,how等等连用构成连用构成不定式短语不定式短语，也可作主语。，也可作主语。e.g.How to use the computer is the question.如何使用计算机是个问题。如何使用计算机是个问题。Where to go has not been decided.去哪儿还没有定下来。去哪儿还没有定下

6、来。【学以致用【学以致用3】完成句子何时出发还没有告知。_ hasnt been told.怎样找到那个走丢的孩子困惑着每一个人。_ confused everyone.When to set offHow to find the lost child3.当主语较长，谓语较短时，常用当主语较长，谓语较短时，常用it作形式主语作形式主语放在句放在句首，而将真正的主语首，而将真正的主语不定式放到谓语的后面不定式放到谓语的后面。e.g.Its not easy to work out the problem.=To work out the problem is not easy.计算出这道题不容易

7、。计算出这道题不容易。It is interesting to play with snow in winter.冬季里玩雪是很有趣的。冬季里玩雪是很有趣的。It is terrible to see the ship sinking into the sea.目睹目睹轮船沉入大海，真是太可怕了。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：作形式主语代替真正主语不定式常见于以下情况中：It is+adj.+for/of sb.to do sth.It is+n.+(for sb.)to do sth.It takes/took/will take sb.som

8、e time/money to do sth.【温馨提示温馨提示】【学以致用【学以致用1】翻译句子/完成句子To be content with little is true happiness._。学好英语是必要的。Its necessary _ 照顾好老人是我们的义务。_ to take good care of the old.知足常乐知足常乐to learn English wellIts our dutyIt is+adj.+for/of sb.to do sth.It is+n.+(for sb.)to do sth.常用于表示常用于表示事物的特征事物的特征，用于，用于此句型的形容

9、词有：此句型的形容词有：easy,hard,difficult,possible,important,impossible,necessary,good,bad,exciting,interesting,surprising等。等。1)It is adj.for sb.to do sth.sb.是是to do sth.的逻辑主语的逻辑主语It is+adj.+for/of sb.to do sth.e.g.It is necessary for young students to learn aforeign language.对对年轻的学生来说，学习一门外语是必要的。年轻的学生来说，学习一门

10、外语是必要的。It is necessary for you to change your job.你你有必要换工作。有必要换工作。It was impossible for them to complete the task in such a short time.他们他们不可能在这么短的时间内完成这项任务。不可能在这么短的时间内完成这项任务。Its important for us to keep the water clean.保持保持水质清洁对我们来说是很重要的。水质清洁对我们来说是很重要的。常见的此类形容词有：常见的此类形容词有：kind,nice,wise,silly,polit

11、e,impolite,friendly,foolish,clever等。等。2)It isadj.of sb.to do sth.形容词用来表示不定式的逻辑形容词用来表示不定式的逻辑主语：主语：人人的的性质、特征或品德性质、特征或品德e.g.It was silly of you to give up such a good chance！你你放弃这么好的一个机会，真傻放弃这么好的一个机会，真傻!Its very kind of you to say so.你你这样说真是太好了。这样说真是太好了。It is friendly of the family to try to make me fe

12、el at home in their house.这这家人对我很友好，使我在他们家里感到宾至如归。家人对我很友好，使我在他们家里感到宾至如归。It was rude of the boy to jump the queue!那个那个男孩插队真是太无礼了男孩插队真是太无礼了!常见的名词有：常见的名词有：pity,shame,pleasure,ones duty,ones job,fun,joy,good manners,bad manners等。等。It is+n.+(for sb.)to do sth.e.g.What a pity it is for you to have missed

13、such a wonderful film.真遗憾你错过了这样一个精彩的电影。真遗憾你错过了这样一个精彩的电影。It must be great fun to fly to the moon in a spaceship.乘乘宇宙飞船飞往月球一定很有趣。宇宙飞船飞往月球一定很有趣。It takes/took/will take sb.some time/money to do sth.做做某事花费某人多长某事花费某人多长时间时间(钱钱)e.g.It took me more than an hour to do my homework yesterday evening.昨天晚上昨天晚上我做作

14、业用了一个多小时。我做作业用了一个多小时。It will take us a lot of money to buy that house.买买那套房子要花费我们很多钱。那套房子要花费我们很多钱。【学以致用【学以致用2】完成句子读这本书对我来说是一种乐趣。Its a pleasure _承蒙您的邀请，真太好了。Its very nice _种这些花花费了我们两个小时的时间。It took us two hours _for me to read the bookof you to invite meto plant these flowers1.No_is permitted here(smo

15、ke)lt is not very good for you_so much(smoke).2._more is necessary(read).lt is quite necessary_it again(read).3._a language in one month is impossible.(learn)一般来说，一般来说，五、不定式和动名词作主语的区别五、不定式和动名词作主语的区别动名词动名词doing作主语表示一种作主语表示一种抽象的和泛指的动作，抽象的和泛指的动作，不定式不定式to do作主语则表示作主语则表示一次性的、具体的动作。一次性的、具体的动作。to smokesmok

16、ing Reading to readTo learn1._(climb)mountains is interesting._(drive)a car during the rush hour must be tiring.2._(teach)English is my job._(teach)you English this term is my job.doing作主语时，通常用以表示一件作主语时，通常用以表示一件已知的事或经验已知的事或经验;to do通常用来表示一件通常用来表示一件未完成的事或目的未完成的事或目的。doing 作主语时强调的是做那件事的作主语时强调的是做那件事的持续状态

17、持续状态;to do作主语时主要表示作主语时主要表示现在或者将来要做的事情。现在或者将来要做的事情。Climbing Driving To teach Teaching3.如果要说明不定式表示的动作是谁做的，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可以在不定式前加一个由 for/of for/of 引起的短语引起的短语,构成构成_。2.不定式作主语时不定式作主语时,可以用可以用it作作_.4.It is+adj.+for sb to do 5.It is+adj.+of sb to do(adj:kind,good,nice,wise,unwise,clever,silly,

18、stupid,foolish,careless,rude,polite,naughty)（修饰（修饰人品人品形容词）形容词）（修饰物的形容词）（修饰物的形容词）1.单个不定式作主语，谓语动词单个不定式作主语，谓语动词_单数单数形式主语形式主语不定式的复合结构不定式的复合结构(adj.:easy,difficult,comfortable,pleasant,light,dangerous，tiresome,interesting,heavy,fit)随堂训练巩固提升.用所给单词的适当形式填空用所给单词的适当形式填空1To make friends with them _(be)nice.2Whe

19、n _(hold)the meeting has not been discussed yet.3_(cross)the Atlantic by plane takes only a few hours.4It made me happy _(find)Mary there.5It is difficult for us _(finish)writing the composition in a quarter of an hour.6Its kind of you _(help)me with my English.isto holdCrossingto findto finishto he

20、lp.完成句子完成句子1出席这个会议对你来说很重要。Its very important _2到那儿用了我们5个小时。It took us five hours _3你把老师说的所有东西都写下来，真是太蠢了。It is stupid of _everything the teacher said.4当你不用车的时候，锁车是有必要的。Its necessary _ when you do not use it.5如何提高产品质量对他来说可是个难题。_ was a difficult problem to him.for you to attend the meetingto get therey

21、ou to write downfor you to lock the carHow to improve the quality of productsJoin the words to make full sentences,and then join the sentences to make a paragraph.You can add your own sentences if necessary to make your paragraph more meaningful.1.important/avoid/passive cigarette smoking It is impo

22、rtant to avoid passive cigarette smoking.2.will take/nutrition specialist/a balanced diet menu/make/an hour/for youIt will take the nutrition specialist an hour to make a balanced diet for you.3.useful/turn to/fitness consultant/for adviceIt is useful to turn to the fitness consultant foradvice.4.il

23、legal/dangerous/take drugs5.harmful/skip breakfast/oftenIt is illegal and dangerous to take drugs.It is harmful to skip breakfast often.n.毒品，药品毒品，药品v.跳过跳过To get healthy and get rid of bad habits,sometimes it is also a good idea to get professional help.It will take an hour for a nutrition specialist

24、 to make a balanced diet menu for you.It is also useful to turn to a fitness consultant for advice.You can also help yourself with some common sense.For example,it is harmful to skip breakfast too often.It is important to avoid passive cigarette smoking.And,of course,it is dangerous to take illegal

25、drugs too.Complete the conversations with the correct forms of the phrases in the box.1.A:Hello,doctor.I want to lose weight,but I just cant seem to do it.What can you do to help me?B:Well,first,its necessary to _ what you eat.Cut out all fatty food and sugary drinks,and eat more fruit and vegetable

26、s.be in control ofbegin with,be in control of,make a choice,decide on,make up ones mind2.A:I really need to _ a way to exercise more.I could use a fitness app,but my phones full.B:So delete a few files.Im sure the app doesnt take up much space.3.A:Before exercising,always do a few warm-ups to _.B:I

27、know.But then I always feel too tired to continue!decide onbegin withbegin with,be in control of,make a choice,decide on,make up ones mind4.A:Should I go for the pizza or the fried chicken?I hate _ like these.You know what Im going to eat both!B:Wow!Dont eat too much junk food youll get fat,Ive actu

28、ally _ to go on a diet,so Ill just stick to the fruit salad.making choicesmade up my mindbegin with,be in control of,make a choice,decide on,make up ones mind1.2019全国全国I卷卷 It is difficult _(figure)out a global population of polar bears.2.2020江苏卷江苏卷 The implication of these results is that to gain th

29、e greatest health benefits from exercise,it may be wise _(skip)eating first.3.2019天津卷改编天津卷改编 Then we will know how important it is _ us to have meaning in our life.to figureto skipfor4.2019天津天津3月月卷卷 Coming out of this experience,I realize it is OK _(be)different from others.5.2018全国全国卷卷 Exercise energizes you,so _ is more difficult to relax and have a peaceful sleep when you are very excited.to beit