人教版高二英语选修六Unit 4 Global warming Grammar课件（35张ppt）

To learn the use of the emphatic “it” and its sentence form “It is/ was …that/ who…”.
观察下面几组句子中it的用法, 然后加以总结。
1. 【语境展示】?
a. It was cholera that killed him.
b. It was Iris that / who found him there.
c. It’s?Lawrence?that? / who?/ whom you should be talking to.
d. It was three weeks later that he heard the news.
【归纳】
it用在强调句中，可以对句子中除谓语以外的成分加以强调。
强调句型的基本结构是：
It is / was +被强调部分+ that / who / whom +句子的其余部分，被强调部分指人时，用who(强调宾语也可用whom)或that，指事物时用_____。
that
2.【语境展示】?
a. Was it in this year that the war
broke out?
b. Is it?Tracy?that / who / whom you
are looking for?
【归纳】
强调句型的一般疑问句形式是：
Is / Was it +被强调部分+ that / who /
whom +句子的其余部分。
3.【语境展示】?
a. Why is it that everyone thinks he is
selfish?
b. What was it that they fought for?
【归纳】
强调句型的特殊疑问句形式是：
________ + is / was it that +句子的其
余部分。
疑问词
4.【语境展示】?
a. It was because I wanted to buy a dictionary that I went to town yesterday.
b. It is what he said just now that makes me angry.
【归纳】
强调句型也可强调状语从句、名词
性从句等。
5.【语境展示】?
a. It must be your mother that? / who?/ whom you are thinking of.
b. It might be my two sisters that / who know her best.
【归纳】
在强调结构中，be前可使用表示推
测的情态动词。
6.【语境展示】?
a. It is not until the end of the year that the traffic laws will take effect.
b. It was not until he was thirty that he started to paint.
【归纳】
not ... until?句型的强调句的形式是：
It is / was not until +被强调部分+ that
+句子的其余部分。
强调句型与其他句型的比较。
1) It is true that I like music.
2) It is music that I like.
3) It is 3 years since I came to No. 1 Middle
School.
4) It is at 10:30 that we have our lesson.
5) It was 10:30 when we had our lesson.
6) It is in this school that I got my first
scholarship.
7) It is this school where we study.
【归纳】
一、强调句与主语从句句型的区别：
从形式上都有：It is…that，所以根据就
是把强调结构标志去掉后，原句在结构意
义上不成立则是___________, 结构与意义
仍然成立的则是____________。
主语从句
强调句
二、当it泛指时间或地点时，常用以下句型：
It is/was+时间段+since 从句（一般过去时/
过去完成时）
It was +时间点+when从句（一般过去时）
It was+时间状语+that…强调句
It is 地点名词+where从句（定语从句）
It is +地点状语+that…强调句
Fill in the blanks.
Today I want to tell you a story. ______ is very interesting. One day I attended my class as usual. _____ was so cold that I closed the door. We were having class when suddenly someone knocked the door. We all wondered who ______ was because no one was absent that day. It was tough _______ (guess) who it really was. It was clear ______ no one knew. So I went up to the door and opened _____ curiously.
It
It
it
to guess
that
it
It was the headmaster ________ stood outside. We were confused. He said to me. “I find _____ unbelievable that you are late for class again”. It took me a few seconds _______________ (understand) what he said. It was no use ___________ (argue) with him. I smiled, “Sorry, headmaster, you mad e a mistake , again.” He went away disappointedly. Our class burst into laughter. Actually I hate _____ when someone interrupts my class.
who/ that
it
to understand
arguing
it
Finish Exercise 2 on page 29:
Rewrite each sentence with It is … that/who … to give more emphasis to the underlined part.
Scientists warned that greenhouse gases would warm the earth by trapping heat energy in the atmosphere.
It was scientists who warned that greenhouse gases would warm the earth by trapping heat energy in the atmosphere.
2. The greenhouse effect gives the earth’s surface the average temperature of 15℃.
It is the greenhouse effect that gives the earth’s surface the average temperature of 15℃.
3. Much of the energy used to light and heart our homes comes from fossil fuels.
It is fossil fuels that much of the energy used to light and heat our homes come from.
4. The developed countries consume the most energy in the world.
It is the developed countries that consume the most energy in the world.
5. Carbon dioxide has the tendency to stay in the atmosphere for centuries while other greenhouse gases stay in the atmosphere only for a day or less.
It is for centuries that carbon dioxide has the tendency to stay in the atmosphere while other greenhouse gases stay in the atmosphere only for a day or less.
6. Low-lying countries feel their very existence is in danger from rising sea levels.
It is their very existence that low-lying countries feel is in danger from rising sea levels.
7. Environmentalists have tried to stop the earth’s temperature rising.
It is environmentalists who have tried to stop the earth’s temperature rising.
8. Scientists want to find out about future climate changes and their effects on our environment.
It is future climate changes and their effects on our environment that scientists want to find out about.
9. In the years ahead, the level of the sea could rise by several meters because of global warming.
It is several meters that the level of the sea could rise in the years ahead because of global warming.
10. In the future outer space might provide us with new energy sources.
It is out space that might provide us with new energy sources in the future.
average
阅读下面句子，并试着归纳average的意思及用法。
The age of the workers ranged from 29
to 49 with an average age of 37.
average 作形容词, 意为: ________。
平均的
In an average week I drive about 250
miles.
average adj. 普通的, 平常的, 一般的
The average of the three numbers 7,
12 and 20 is 13.
average n. 平均数
On average, men still earn more
than women.
Temperatures are above / below
average for the time of year.
average n. 平均水平，一般水准
__________ 平均
above / below average
在平均水平以上/以下
on average
Economic growth is expected to
average 2% next year.
average v. 平均为
Choose a topic you like (eg global warming, wildlife protection, music, film. etc) for this activity. Work in groups and try to tell the information you know about the topic using emphatic “it”.
EXAMPLE:
It was during the 20th century that the temperature of the earth went up about one degree Fahrenheit.
It was Charles Keeling who made accurate measurements of the amount of carbon dioxide in the atmosphere.
It was only when the car pulled up in front
of our house ___________ we saw Lily in the passenger seat. （2018天津6月）
2. What was it _______ brought you two together? Was it your love of music? （2018天津3月）
that
that
I. 对画线部分内容进行强调。
1.?The washing machine?needs repairing.
_______________________________
_______________________________
2. I met?Henry?in?New York.
_______________________________
_______________________________
It is the washing machine that needs repairing.
It was Henry that / who / whom I met in?New York.
3. Tom went to?London?on Tuesday.
_________________________________
_________________________________
4. We will wait for him?at the coach station.
_________________________________
_________________________________
5. They did?not?see each other again?until
the fall.
_________________________________
_________________________________
It was on Tuesday that Tom went to?
London.
It is at the coach station that we will wait for him.
It was not until the fall that they saw each other again.
II. 根据汉语意思运用强调结构补全下面句子。
1.?三个星期以后他才听到这个消息。
__________________________ he heard the news.
2.?他在会上说的话让我很生气。
___________________________________ made me really angry.
3.?是彼得借钱给我们的。
______________________ lent us the money.
It was three weeks’ later that
It was what he said at the meeting that
It was Peter who / that
4.?他们准备去的是西班牙，不是法国。
_______________ they’re going to, not France.
5.?直到去年夏天我才接到她的来信。
_____________________________ I heard from her.
6.?你昨天是在哪里碰到露西的？
_______________ you met Lucy yesterday？
It’s Spain that
It was not until last summer that
Where was it that
1. Review what we have learned this class.
2. Finish the exercises 1, 2 on page 64.