● Walk or ride a bike instead of using motor vehicles if you can.
● Recycle cans, bottles, plastics and newspapers; buy things made from recycled materials.
● Buy products that are made to save energy such as fridges and microwaves.
● Plant trees in your garden or school yard.
Together, individuals make a difference. It’s time for us to do something about carbon dioxide. Talk with your friends or family about global warming. Let’s work together and care the planet we are living in.
Step Ⅱ Discovering words and expressions
T: Now please open your books and turn to page 28. Let’s do some exercises.
Step Ⅲ Discovering useful structures
T: Next let’s turn back to page 29. We’ll learn a useful structure. Now compare these two sentences below. Show the following two sentences on the screen. Human activity has caused this global warming. It is human activity that has caused this global warming. T: Who can translate them into Chinese?
Sa: I think they are the same. They both mean“人类行为引发了
全球变暖”.
Sb: I don’t think so. They are a little bit different. The latter one should be “引发全球变暖的正是人类行为”. In the second sentence, “human activity” is emphasized.
T: Quite right. This is the structure we are going to learn today. Present the structure on the screen and give some explanation. 由it 引导的强调句结构:
It is (was) + 被强调部分 + that (who) + 句子其他部分 注意：此结构强调的成分仅限于主语，宾语和状语。 如：
原句：My father did the experiment in the lab yesterday evening.
强调主语： It was my father who did the experiment in the lab yesterday evening.
强调宾语： It was the experiment that my father did in the lab yesterday evening.
强调时间： It was yesterday evening that my father did the experiment in the lab.
强调地点： It was in the lab that my father did the experiment yesterday evening. 又如：
It was in that city that we met for the first time.
It was not until he told me that I knew the truth. 典型例题分析:
1）It was last night _______ I saw the film Star Wars. A. who B. when C. that
D. which
答案C. 强调句的结构是： It + be + 强调部分 + that (who) + 主谓句。强调句的连词只有两个，that和who。当强调的部分是人，且为句子的主语时，才用who，其余用that。 2）It is ten years _______ Miss Green returned to Canada. A. that
B. when C. since D. as
答案C. 考点是连词用法。 本题易误选为A.
其实本句不是强调句。若是，去掉It be ... that还应是一个完整的句子。而本句去掉‘It is ...that’，只剩下ten years Miss Green returned to Canada不成句。因此本句不是强调句。 It is + 时间 + since ..., 其中is = has been.
T: In the article there are two sentences in which “it” is used for emphasis. Can you find them?
Sc: Yes. One is “It was a scientist called Charles Keeling who made accurate measurements of the amount of carbon dioxide in the atmosphere from 1957 to 1997.” The other is “It is the burning of more and more fossil fuels that is resulting in this increase in carbon dioxide.”
T: Good. Next let’s do some practice about this structure. Turn
to page 29, Exercise 2. Please rewrite each sentence with “It is ... that ...” to give more emphasis to the underlined part. Sample answers:
1. It is greenhouse gases that have warmed the earth by trapping heat energy in the atmosphere.
2. It is the greenhouse effect that gives the earth’s surface the average temperature of 15℃.
3. It is fossil fuels that much of the energy used to light and heat our homes comes from.
4. It is the United States of America that the biggest producer of greenhouse gases is.
5. It is for centuries that carbon dioxide stays in the atmosphere while other greenhouse gases stay in the atmosphere only for a day or less.
6. It is their very existence that low-lying countries feel is in danger from rising sea levels.
7. It is human activities that many scientists believe that have caused the earth’s temperature to rise.
8. It is future climate changes and their effects on our environment that scientists want to find out about. 9. It is by several meters that the level of the sea could rise because of global warming in the years ahead.
10. It is outer space that might provide us with new energy sources in the future. Step IV Using structures
Get the students to do more exercises about the use of “it” for emphasis.
T: Please turn to page 64. Read the instructions of the two exercises and then finish them. Sample answers to Exercise 2:
(1) It was four Australian children who started it in 1996 when they organized the first children’s environmental conference. (2) It is at this conference that we decide which projects we want to work on in the following year.
(3) It was through one of these projects about five years ago that I first became involved in Millennium Kids. Step Ⅵ Homework
Make four sentences with “it” for emphasis. The Fifth Period Drills Teaching goals 教学目标 1. Target language 目标语言 a. 重点词汇和短语
environmental problem, plastic bags, reuse, litter, rubbish items, Clean Up Day, bring up
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