资源简介

(共25张PPT)
Unit
4
Oxford English
Module 2 Environmental problems
Period 3
Grammar
Natural disasters
To learn to use it as the empty subject
Objective
Using it as the empty subject (I)
Have A L k
It’s nine o’clock in the morning. My bedroom floor is a pool of water.
It is one o’clock.
It is summer now.
It rained all day.
It is only a five-minute walk from my home to the school.
It is hot in this room.
Observe these sentences and think about what it refers to.
the time
the season
the weather
the distance
the temperature
time
season
weather
代词it可用作主语，表示时间、季节、天气、温度或距离等。如：
It is half past twelve.
It is spring.
It is fine today.
It is twenty-five degrees centigrade.
It is two kilometres to the post office.
it 的用法 I
Translate the following Chinese sentences into English.
现在是十点十分。
宾馆距离海滩两英里远。
今天早晨下雨了。
今天天气相当暖和。
It’s ten past ten.
It’s two miles from the hotel to the beach.
It was raining this morning.
It’s quite warm today.
Answer the questions using it as the subject. (P 55)
A
It is sunny.
It is twelve o’clock.
It is February 18th.
It is spring.
It is five kilometres.
Put the words in the correct order to make meaningful sentences. (P 56)
B
It is time for supper now.
It is autumn in Australia now.
It is about five kilometres to the park.
It was windy yesterday.
Using it as the empty subject (II)
Have A L k
My boss has given me some work. It’s important to stick with it.
2. It took a long time to build the house.
3. It is wrong to pay no attention to Kevin.
4. It is not a good idea to sit around and worry about the flood.
Observe these sentences and think about what it refers to.
形式主语
真正的主语
当句子的主语是动词不定式短语时，一般用代词it 作形式主语放在句首，而将真正的主语动词不定式短语放在句末。如：
It is pleasant to sit in the Sun.
It was a pleasure to sit in the Sun.
it 的用法 II
It + is/was +形容词/名词+ to do sth.
Rewrite the sentences below using it as the empty subject.
1.To eat healthily is very important.
2.To study two languages is very hard.
3.To find out the truth is important.
It is very important to eat healthily.
It is very hard to study two languages.
It is important to find out the truth.
Write a sentence using it and a to-infinitive under each picture below. (P 57)
C
It is important to stay calm when there is a fire.
It is dangerous to start a fire in the forest.
It is a good idea to take an umbrella.
It is nice to have a picnic in the park.
注意：有时动词不定式有自己的逻辑主语，常由 “for/of + sb.” 构成。
“It + is/was + adj + (for/of + sb) + to do sth.”
★ (for sb) 若形容词描述事物的特征性质, 如: easy, useful，important, dangerous等
★ (of sb) 若形容词描述人物的性格品质, 如: kind, polite, nice, careful等
Fill in the blanks with for/of
It is impossible ____ me to finish the writing in half an hour.
It is not easy ____ him to learn English well.
It is clever ____ you to leave at once.
It is very kind ____ you to think so much for others.
for
for
of
of
it 作为形式主语还常见于It seems / appears that… 的句型中。如：
1. It seems that it is going to rain.
2. It seems/appears that nobody is paying any attention to the flood.
Translate the following Chinese sentences into English
似乎没有一个人相信Kevin说的话。
It seemed/appeared that nobody believed Kevin.
你爸爸似乎并不了解你。
It seems/appears that your father doesn’t understand you.
看样子Jim不太喜欢我。
It seems/appears that Jim doesn’t like me.
Put the words in brackets in the correct order to complete the conversations. (P 57)
D
It seems that a typhoon is coming.
It appears that the flight has been cancelled.
It seems that something bad has happened to her.
Using it as the empty subject
Ⅰ it可用作主语，表示时间、季节、天气、温度或距离等。
Ⅱ it 作形式主语代替真正的主语（动词不定式短语）
It + is/was + adj/n + to do sth.
It + is/was + adj + (for/of + sb) + to do sth
it 作为形式主语还常见于It seems / appears that… 句型中
It seems/appears that…
Summary
To have a good knowledge of history is very helpful for all of us.
To learn a foreign language is very useful for a scientist.
To finish this work in three hours is necessary.
It is very helpful for all of us to have a good knowledge.
It is necessary to finish this work in three hours.
It is very useful for a scientist to learn a foreign language.
I. 用it作形式主语改写句子。
现在十点半了。
好像他又犯了同样的错误。
在那个城市夏天炎热冬天寒冷。
很容易理解他为什么没回来。
It is ten thirty now.
II. 翻译下列句子。
It appears/seems that he has made the same mistake again.
It is hot in summer and cold in winter in that city.
It is easy to understand why he has not come back.
H
Homework
1. 用it作形式主语，改写下列句子。
To have a good knowledge of history is very helpful for all of us.
To learn a foreign language is very useful for a scientist.
To finish this work in three hours is necessary.
To sit by the fire with a book in winter is very comfortable.
To guess where they are is difficult for me.
To see you staying in bed all the time makes me feel sad.
2. 汉译英。
他来到饭店的时候，已经是12点50分了。
照顾孤儿是他的职责。
修车花了我一百美元。
看样子她得了重感冒。
3. 复习今天所学的语法并整理笔记。

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