教案 4 人教选修6 Unit4 Global Warming
Grammar
Teaching material
NSEFC Book 6 —— Unit 4
Teaching aims
Enable the students to master the usage of the form it is/was... that.....
Teaching important points
How to enable the students to know the structure and the usage of the form it is/was... that....
Teaching difficult points
How to help the students to master the usage of the form it is/was... that....
Teaching aids
tape recorder, slides
Teaching procedures
Step1 Revision
T: First let’s check answers. (slide show)
Discovering useful words and expressions. (P28)
1. Charles Keeling collected ______on the carbondioxide content in the atmosphere over a forty-year period. He found that the amount of carbondioxide _______ increasing during that time.
2. Although we are burning coal in huge _________ every year, we won't ________ of it for centuries.
3. If the amount of greenhouse gases continues to _______ we could be facing a global __________.
4. Many scientists believe that global warming has __________ through the burning of fossil fuels. They do not think that ignoring the issue is worth the ____.
5. ______ describes weather conditions over a period of years in a particular place.
6. The _____________ of a rising sea level would be widespread flooding.
7. The use of energy in Susanna's country is low ______________ the use of energy in the USA.
8. The warming of the earth is a _____________ that causes great concern.
9. The ________ shows temperature changes during the 20th century.
10. One hectare of forest can absorb 23 tons of carbondioxide ____ year.
Keys：1.data kept on 2. quantities; run out 3. build up; catastrophe
4. come about; risk 5. Climate 6. consequence 7.compared to 8.phenomenon
9. graph 10. per
Answer keys for Ex.2 on Page 28:
The first graph shows the global _______________ between ________ and _________The temperature __________ and decreased over this period but on the whole it _________ by around _________ and its highest in 2000. There was a steady _________________ in the temperature during the twenty years after 1980. We can see from the graph that the earth has become ___________ since early last century.
The second graph shows the amount of ______________in the atmosphere from ________ to _______ .The carbondioxide __________ steadily over this forty-year period. It went up from 315 to 370 parts ___________million.
Keys：
Temperature；1860；2000；increased；rose；1910；increase/rise；warmer
carbon dioxide；1957；1997；increase/ went up；per
Step2 Grammar
强调句结构
常考的强调句结构是it 引导的句子。
It is (was) 被强调部分+ that (who) + 句子其他部分。此结构强调的成分仅限于主语，宾语和状语。
It is from the sun that we get light and heat.
It was not until I had read your letter that I understood the true state of affairs.
Karl bought Marva a bicycle on her birthday．卡尔在玛瓦生日那天给她买了一辆自行车。 
It was Karl that／who bought Marva a bicycle on her birthday．（强调主语） 
It was Marva for whom Karl bought a bicycle on her birthday．（强调间接宾语） 
It was a bicycle that Karl bought Marva on her birthday．（强调直接宾语）
注意区别强调句中的that／who分句与定语从句： 
It was the student that／who asked the silly question．是一个学生问了这么一个愚蠢的问题。（分裂句） 
He was the student who asked the silly question．他就是问了这么一个愚蠢问题的学生。（划线部分是定语从句） 
二、not ... until ... 的强调形式: It is not until + 被强调部分 + that ... “直到…才…”， 主要用于强调时间状语的强调句型。
We did not begin studying French until we entered university．我们进了大学才开始学法语。 要强调until we entered university，就成了： 
It was not until we entered university that we began studying French． 
______ the 18th century that man realized that the whole of the brain was involved in the workings of the mind． 
A. During B. In C. It was until D. It was not until
 D对。直到十八世纪，人们才意识到：心理活动与整个大脑有关。
 三、强调句的疑问句句型
1.强调句的一般疑问句句型:
Is / Was +it +所强调的部分+that
生词表: