人教版（2019）选择性必修第三册Unit 2Bridging Cultures Discover useful structures 课件(14张ppt)

(共14张PPT)
Period 3 Discovering useful structures
The infinitive of the verb used as the subject
Unit 2 Healthy Lifestyle
单元语法自我探究
Look at the following sentences and pay attention to the italicized infinitives. Find more infinitives in the reading passage, and tell their meanings and functions.
1. To change bad habits is never easy.
2. It took the surgeon three hours to finish my mother’s lung surgery.
3.To join the people’s 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.
主语
主语
主语
目的状语
动词不定式作主语时，谓语动词用单数。
To look after these naughty boys is really difficult.
To get up early is necessary.
To learn a skill is important for everyone in society.
To change bad habits is never easy.
It作形式主语，动词不定式作真正的主语放在句末。
It took the surgeon three hours to finish my mother’s lung surgery.
基本用法
Observe
Observe and Discover
1. It isn’t right to talk like that.
2. It’s difficult to master English.
3. It’s hard for me to answer the question.
4. It is important to learn a useful skill.
Discover
1.以上句子的真正主语都是____________，但都使用it作形式主语；
2.以上句子的表语都是______。
动词不定式
形容词
Find more infinitives in the reading text.
1….it can be easy for some of them to form bad habits.
2. After all, it is not easy to break bad habits.
3. ... ...
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it做形式主语，而真正的主语放在句子末尾。
Their meanings and functions
Find and Discover
Group Work
语法研析
不定式作主语，it 做形式主语的常见结构：
1. It is +adj.+(for sb) to do
It is easy for me to learn how to drive.
2. It is +adj.+(of sb) to do
It is clever of you to apply for the position.
3. It is +n.+ to do sth( an honour, our duty, a pity, a shame)
It is our duty to take care of you.
4. It takes/took sb some time to do sth.
It takes me half an hour to do my housework.
It is +adj.+(of sb) to do
1. 对我来说每天读英语是很重要的。
2. 你真是太好了，能帮我学英语。
3. 能帮助你是我的荣幸。
4. 我每天花15分钟读英语。
Translation
It is very kind of you to help me learn English.
It is +adj.+(for sb) to do
It is +n.+ to do sth( honour, duty, pity)
It takes/took sb some time to do sth.
It takes me 15 minutes to read English everyday.
It is my honour to help you.
It is important for me to read English everyday.
语法研析
It is important for me to read English everyday.
It is very kind of you to help me learn English.
It is+adj+for sb to do …… 表示事物的特征特点
(adj: easy, difficult, comfortable, pleasant, light ,
dangerous, tiresome, interesting , heavy, fit)
(adj: kind, good, nice, wise, unwise, clever, silly, stupid, foolish, careless, rude, polite, naughty)
It is+adj+ of sb to do…… 表示人物的性格品德
客观
主观
4. It is important ______ Tom to get that job.
5. It is kind ______ you to help me with my work.
1. _________( talk ) with him is a great pleasure.
2. __________( help ) others is our duty.
To talk
To help
=It is our duty to help others.
for
of
3. It is easy_____ the students to read.
Practice
for
把句2改为It作形式主语的句子
1. To improve people’s lives _____ an important task for our government.
3. To be a good doctor _______ (need) years of hard work.
2. It’s silly _____ you to give up such a good chance.
4. To get the work done as quickly as possible ______ what I wanted.
is
of
needs
is
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_______________.
it作形式主语的几个句型是？
It is+adj+for sb to do ……
It is+adj+ of sb to do……
（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
Summary
Join the words to make full sentences using 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
Homework
Excersie 2 P17
1. important/avoid/passive cigarette smoking.
It is important avoid passive cigarette smoking.
2. will take/nutrition specialist/a balanced diet menu/make /an hour/for you.
It will take a nutrition specialist an hour for you to make a balanced diet menu.
3.useful/turn to/fitness consultant/for advice
It is useful to turn to fitness consultant for advice.
4.illegal /dangerous/take /drugs
It is illegal and dangerous to take drugs.
5.harmful/skip breakfast/often
It is harmful to often skip breakfast.
Homework
Thank you!