1、Discovering Useful Structures By the end of this period,you will be able to1.master the usage of the infinitive as subject.2.use the relevant grammar flexibly and authentically in real situation.3.understand the difference between the infinitive as subject and V-ing form as the subject.1.To change b
2、ad habits is never easy.2.It took the surgeon three hours to finish my mothers lung surgery.3.To join the peoples Liberation Army,it is required for men to shave off their beards.4.It was not polite to disturb your neighbors with loud music last night.Look at the following sentences and pay attentio
3、n to the italicized infinitives,and tell their meanings and functions.meanings and functions The infinitive in each sentence functions as the subject of the sentence.Summary 1Meanings and functions of the infinitive of the verb as the subject.动词不定式在句中做主语，有时为了保持句子的平衡，动词不定式在句中做主语，有时为了保持句子的平衡，避免头重脚轻，常用
4、避免头重脚轻，常用itit做形式主语，而真正地主语放做形式主语，而真正地主语放在句子的末尾。比如第在句子的末尾。比如第2,3,42,3,4例句。例句。1_ 2_ .Activity 1 Find more infinitives in the reading passage.it can be easy for some of them to form bad habits.After all,it is not easy to break bad habits.Activity2:Fill in the blanks using the right form of the word,and
5、try to change it in another sentence pattern.Step II Self-directed study1.It is important _ Tom to get that job.It is kind _ you to help me with my homework.2._(talk)with him is a great pleasure.It is_3._(help)others is our duty._4.It took Tom 2 hours _.(作准备)forofTo talkTo helpto make preparations a
6、 pleasure to talk with him.It is our duty to help others.Summary 2:例例1.It is+adj.+(for sb)to doeg:It is easy for me to learn how to drive.学开车对我来说很轻松。学开车对我来说很轻松。It is+adj.+(of sb)to doeg:It is clever of you to apply for the position.你申请这个职位真是明智的。你申请这个职位真是明智的。例例2.It is+n.+to do sth(an honour,our duty,
7、a pity,a shame)eg:It is our duty to take care of you.照顾你是我们的责任。照顾你是我们的责任。例例3.It takes/took sb some time to do sth.It takes me half an hour to do my housework.我花了半个小时做家务。我花了半个小时做家务。不定式作主语，it 做形式主语的常见结构：To look after children is her job today.她今天的工作是看孩子。她今天的工作是看孩子。Looking after children is her work.她的
8、工作是照顾孩子。她的工作是照顾孩子。Summary 3不定式作主语和动词不定式作主语和动词-ing形式作主语的区别：形式作主语的区别：Activity3:Compare the two sentences below and tell the difference in meaning.动词动词-ing形式和不定式作主语形式和不定式作主语,都是说明一个内容。都是说明一个内容。不定式通常表示一个将来的、具体的内容不定式通常表示一个将来的、具体的内容;但是但是,而动词而动词-ing形式则表示一种经常性的、习惯的或抽象的概念。形式则表示一种经常性的、习惯的或抽象的概念。More examples:S
9、moking is prohibited here.这里禁止抽烟。(抽象)It is not very good for you to smoke so much.你抽这么多烟对你身体很不好。(具体)Climbing mountains is interesting.爬山很有趣。(已知的事或经验)To finish the task will take a long time.要完成这项任务将要花费很长时间。(未完成的事或目的)Step III Complete the sentences.Activity 4 Join the words to make full sentences usi
10、ng the infinitive.1.important/avoid/passive cigarette smoking._2.will take/nutrition specialist/a balanced diet menu/make/an hour/for you._3.useful/turn to/fitness consultant/for advice_4.illegal/dangerous/take/drugs_5.harmful/skip breakfast/often_It is important to avoid passive cigarette smoking.I
11、t will take a nutrition specialist an hour for you to make a balanced diet menu.It is useful to turn to fitness consultant for advice.It is illegal and dangerous to take drugs.It is harmful to often skip breakfast.Summary4:1.单个不定式作主语，谓语动词单个不定式作主语，谓语动词 _ 2.不定式作主语时不定式作主语时,可以用可以用 it 作作_.单数单数.形式主语形式主语 S
12、tepIV.Analyze the sentence patterns Activity5:单句语法填空单句语法填空（1）Sometimes its better （remain）silent.（2）Although is a hard task to protect our environment，we cant help but go ahead.（3）（control）the air pollution is necessary.（4）It was foolish him to endanger his life in that way.（5）Dont you think it is r
13、ude him to ask a lady her age?（6）It is difficult him to live on such a small salary.to remain it To control/Controlling of for of Summary 51.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由 for/of 引起的短语引起的短语,构成不定式的复合结构。构成不定式的复合结构。2.It is+adj+for sb to do（修饰物的形容词）（修饰物的形容词）(adj.:easy,difficu
14、lt,comfortable,pleasant,light,dangerous，tiresome,interesting,heavy,fit)It is+adj+of sb to do（修饰人品形容词）（修饰人品形容词）(adj:kind,good,nice,wise,unwise,clever,silly,stupid,foolish,careless,rude,polite,naughty)1.A:Hello,doctor.I want to lose weight,but I just can t seem to do it.What can you do to help me?B:We
15、ll,first,its necessary to _ what you eat.Cut out all fatty food and sugary drinks,and eat more fruit and vegetables.2.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
16、 do a few warm-ups to_.B:I know.But then I always feel too tired to continue!4.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 actually _ to go on a diet,so Ill just stick to the fruit salad.b
17、e in control of decide onbegin with to make choicesActivity 6 Complete the conversation with the correct forms of the phrases in the box.made up my mind begin with be in control of make a choice decide on make up ones mind 1 (lean)out of the window is dangerous.2 (save)money now seems impossible.3It
18、 is an offence (drop)litter in the street.4It is stupid of you (write)down everything(that)the teacher says.5_(say)is one thing and to do is another.6It seemed a pity _(waste)so much time.7.I dont think _（你问（你问是不礼貌的）是不礼貌的）how long the interview will last.8.（保卫（保卫 是我们的职责）是我们的职责）the country against it
19、s enemies.9.（花了我半个小时）花了我半个小时）to wash the clothes.To lean To save to dropActivity 7.Complete the sentences using the correct forms of the words.to write To say to have wasted it is impolite of you to ask Its our duty to defend It took me half an hour 1.I like eating fried tomatoes with eggs,and I tho
20、ught it must be easy_(cook).2.It is easy for them _(care)for.3.It was so good _(feel)accepted for what Im good at.4.Its my first time_(hear)Chinese stories told by an English speaker.to cookto be caredto feel to hear 5.Then we will know how important _ is to have meaning in our life.6.It is not a simple matter_(determine)the nature of talent.7._(learn)to think critically is an important skill todays children will need for the future.8.On our way to the house,it was raining so hard that we couldnt help wondering how long it would take _(get)there.it to determineLearningto get
