人教版（2019）选择性必修第三册Unit 2 Health lifestyle Healthy lifestyle Discover useful structures 课件(共18张PPT)

(共18张PPT)
UNIT 2 HEALTHY LIFESTYLE
Infinitives as the subject
Discover useful structures
1. However, during this period, it can be easy for some of them to form bad habits.
2. To prevent harmful habits like these from dominating a teenager’ s life is essential.
3. To change bad habits is never easy, even with many attempts.
4. After all, it is not easy to break bad habits.
5. When to hold the sports meeting has not been decided.
Observe and Discover
Look at the following sentences and pay attention to the infinitives. P36
【语法感悟】
①在句1、4中，it是　　　　　　，代替后面的动词不定式短语。
②在句2、3中，To prevent...和To change...都是动词不定式短语作　　　　　________。
③在句5中，When to hold...是“疑问词+to do”结构，该部分在句中作　　　　　。
形式主语
主语
主语
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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。
一【含义】
不定式作主语一般表示具体的或某一次的或将来的动作, 谓语动词用单数。
To know something about English is one thing; to know English is quite another.
懂一点英语是一回事；掌握英语完全是另一回事。
注：单个不定式作主语时，谓语用单数形式；两个及以上不定式作主语时，谓语用复数形式；但作为一个整体时，谓语用单数形式。
Where to go on a holiday and when to go for the holiday _____(have) not been decided.
Where and when to go on a holiday ______(have) not been decided.
have
has
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，how
whether
E.g.
How to break the bad habit is the question.
Where to go hasn't been discussed.
It has not been decided whether to fly to Paris.
”疑问词+to do”作主语
【Practice】Use the correct forms of the words to fill in the blanks.
When ________ (start) has not been decided yet.
How ________ (use) the computer is the question.
It has been decided where ________ (spend) our winter holiday.
to start
to use
to spend
二【位置】
1. To prevent harmful habits like these from dominating a teenager's life is essential.
2. To change bad habits is never easy, even with many attempts.
3. After all, it is not easy to break bad habits.
4. However, during this period, it can be easy for some of them to form bad habits.
句首
it作形式主语, 不定式放句尾
考点二：it 作形式主语常见的句型
1. It is+形容词+for/of sb +to do sth
E.g.
It is easy for me to learn how to drive.
It is clever of you to apply for the position.
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;
2. It is+名词(a pleasure/a pity/an honour...) (for sb)+ to do sth
E.g.
It is an honour to give a speech in behalf of my school.
It is a pity to miss the chance to see your show.
3. It takes/took/will take sb. some time/money to do
做某事花费,某人多长时间(钱)
E.g.
It took me more than an hour to do my homework yesterday evening.
　完成句子
①It seemed selfish of him 　not to give his employees anything　 .
他不给员工任何东西，这显得他太自私了。
②It seems a pity 　to refuse the invitation　 .
拒绝这份邀请似乎是遗憾的。
③It’s unwise 　of them to turn down the proposal　 .
他们拒绝（采纳）这个建议是不明智的。
④It will be a mistake 　for us not to help them　 .
我们不帮助他们将是错误的。
not to give his employees anything　
to refuse the invitation　
of them to turn down the proposal　
for us not to help them　
It will take the nutrition specialist an hour to make a balanced diet menu for you.
It is useful to turn to the fitness consultant for advice.
It is illegal and dangerous to take drugs.
It is often harmful to skip breakfast.
拓展1：it 作形式主语,doing作真正的主语
1. 浪费时间做某事:
2. 做某事是没有用的：
3. 做某事是没有乐趣的：
4. 做某事是没有好处的：
It is a waste of time doing sth
It's no use doing sth
It is no fun/pleasure doing sth
It is no good doing sth
拓展2：to do和doing作主语的区别
To look after children is her job today.
她今天的工作是看孩子。
Looking after children is her work.
她的工作是照顾孩子。
区别
to do 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)
　单句语法填空
① 　To hear　 （hear） your voice is so nice.
② 　To look　 （look） after the safety of the community is his responsibility.
③ 　Smoking　 （smoke） is prohibited here.
④How 　to cure　 （cure） this kind of illness is still unknown.
To hear　
To look　
Smoking　
to cure　
be in control of
decide on
begin with
making choices
made up my mind
How can we lose weight
to do
作主语
to do 作主语位于句首,
谓语动词用单数
it 作形式主语
疑问词+to do 构成不定式短语
和-ing 作主语的区别
To read without reflecting is like eating without digesting.
It takes sb. time/money to do sth.
It is + adj. + (for/of sb.) to do sth.
It is + n. + (for sb.) to do sth.
to do 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
1 A: I'm thinking about riding a motorbike to school. What do you think
B: Oh Well, I think it's necessary ________________________________ first.
2 A: How come you fainted suddenly yesterday Didn't you eat anything in the morning
B: I'm on a diet.
A: That's so bad! You know it's important _____________________ every morning.
3 A: I often see you around Central Park.
B: Yes, I like _______________________ there every weekend. We usually play ball games.
4 A: I hear that the new headmaster has too many things to do.
B: Yes. It will be a big challenge for him_____________________________________.
A group of students are chatting after plete the conversations with the correct forms of the phrases in the box.
eat a good breakfast get your parents’ permission
hang out with friends balance work and personal life
to get your parents’ permission
to eat a good breakfast
hanging out with friends
to balance （his） work and personal life
(WORKBOOK P69 EX. 1)
It will take us about half an hour________________（到达）the West Lake. In the morning, we will visit the places of interest around or near the West Lake, including the lake, Gu Hill, Lingyin Temple, and Lei Feng Pagoda. This will be a good chance_____________（欣赏）the beautiful scenery as well as the history and culture of Hangzhou. In the afternoon we may_______（尝试）a taste of Longjing Tea and ___________ （看电影）. For the evening, there are many things we can choose from, like dinner, shopping, and experiencing the local night life. It will be fun for us___________（选择）together what we want to do after you arrive.
A holiday is a perfect time to relax. You are planning a trip to Hangzhou for your American plete the paragraph about your plan.
to reach/get to
to appreciate
have
see a movie
to choose
(WORKBOOK P69 EX. 3)