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第二冊第34課
CAI Demonstration Class
Saving The Earth
October 16,2000
By Zhaoxiang Zhou
I. Teaching focus
1.Realize the damage caused to the world and figure out the reasons.
2.Find ways to stop the earth from being polluted by discussing in groups.
II.Teaching approaches
Elicitation, Mutual Interaction
III.Teaching aid
Interactive multimedia teaching
IV.Teaching process
Step 1 Revision
1. Check note-making
Earth: not enough rain, too many cattle, cutting down trees, strong winds
Air: smoke from factories, power stations, cars, chemical rain, accidents at power stations and factories
Water: waste from factories and cities
Step 2 Presentation
1． Present a series of images depicting the natural beauty of the earth, then the pollution. Highlight the sharp contrast between them. Guide the students to the conclusion: The earth used to be much more beautiful than now; the earth is in danger due to the increasing pollution.
2． Study the map on the textbook, then scan the passages to figure out where on the world atlas the damage has happened. Encourage the students to give out their point of view toward the pollution issue.
Step 3 Audiovisual Learning
The students watch a video on the text, then do the following true or false questions.
1. Many parts of the world with large population and plenty of crops have become deserts. T
2. Land may become poor if farmers do not limit the numbers of their cattle. T
3. Good soil is gradually lost these days as trees are being cut down. T
4. Air pollution and water pollution are the two causes of the problem that many parts of the world have become deserts. F
5. Chemicals in the smoke from power stations can travel hundreds of miles in the wind before falling down to the ground in the rain. F
6. After a bad accident at a nuclear power station, 50% of the trees in
7. The writer to explain how water is polluted uses the examples of the accidents in both
8. Once oceans are polluted, they are not able to clean themselves. F
Step 4 Intensive
Read the passages again for some detailed information
1. To say something about the damage that is caused to the world by pollution, using the information from the text. Try to present possible ways to help solve the problems.
Phenomena
Causes
Suggestions
E
A
R
T
H
The area of desert is growing every year.
Cattle eat grass.
Limit the number of the cattle.
Good soil is gradually lost.
Trees being cut down; strong winds blowing the valuable soil away.
Plant more trees and try to protect them.
A
I
R
Air is being polluted.
Factories, power stations and cars produce a lot of waste.
A lot of things have to be done to reduce pollution. New laws should be passed and people should realize how serious the problem is.
A lot of people died from polluted air in both
There were serious accidents that polluted the air.
Trees in the forest are destroyed and fish in the lakes are killed.
Chemical rain.
W
A
T
E
R
In some places it’s no longer safe for swimming, nor is it safe to eat the fish.
Factories and cities produce a lot of waste.
Same as above.
Waste produced from a chemical factory.
2.to summarize the text by giving the main idea of each passage.
Earth:
The area of desert is growing and good soil is gradually lost.
Air:
Chemicals in the smoke cause a lot of damage and serious accidents took place
from time to time.
Water:
Water pollution is caused by man’s waste. The waters of this great lake have been dirtied and 4800 square km of ocean were polluted by oil.
Step 5 Discussion
Appoint one student to host the discussion. The rest of the class fall into groups of 4, changing ideas on the following question.
(1)What kind of pollution can you think of?
(2)Why trees are important?
(3)What are the causes of water pollution?
(4) What can be done to stop land from becoming into desert?
(5) What else do we know about the problems that the earth is facing?
(6) What steps should we take to save the earth?
Step 6 Role play
The students take turns to play the role of a newspaper reporter, making interviews with heads of factories (e.g. A papermaking factory) which are seriously polluting air and/or water. Record the interviews and compose a report.
Step 7 Assignment
（1）Read the additional materials about pollution and do the reading comprehension exercises.
（2）Finish the report.
Thanks for attending this class!
_____________________________________________________________________________--__
資料 我國環(huán)境污染現(xiàn)狀令人擔(dān)憂
據(jù)專家估計，中國每年因環(huán)境污染造成的損失達到二千八百三十億元人民幣，其中，僅水污染一項，估計一年造成經(jīng)濟損失約五百億元。
據(jù)香港《東方日報》報導(dǎo)，自六十年代至今，中國有環(huán)境監(jiān)測的四百三十二條大小河流中，八成受到不同程度的水體污染，其中大江河經(jīng)過城鎮(zhèn)河段的占二成，支流受污染的占六成，全中國二千八百多個湖泊，凡能接納城鎮(zhèn)污水的，大多出現(xiàn)水體負氧化現(xiàn)象。由于地下水過度開采，京津滬大面積出現(xiàn)土地沉降一點五公尺至二公尺，桂林溶巖區(qū)三
大氣污染造成的經(jīng)濟損失約為二百億元，由于城市燃煤、工廠排放廢氣及汽車死氣污染，大氣中二氧化硫、一氧化碳等有毒懸浮微粒彌漫在城市上空，空氣污染導(dǎo)致許多城市肺癌死亡率增至萬分之二，全國酸雨覆蓋面積已達百分之三十，所有這些損失加起來也等于二百億元。
而生態(tài)環(huán)境破壞和自然災(zāi)害造成的損失估計高達二千億元，森林覆蓋率由四九年的三成左右，現(xiàn)已下降至不足一成四，草原的嚴重退化，水土流失面積達一百五十五萬平方公里，占國土面積的百分之十六。
同時，城鎮(zhèn)建設(shè)卻仍以每年侵占一百五十萬公頃土地的速度發(fā)展，破壞自然生態(tài)平衡，加上自然災(zāi)害帶來的損失，每年至少損失二百億元。
其他污染如固體廢物排放、噪音污染等造成的損失也高達一百三十億元。
專家分析表示，造成環(huán)境污染引起的經(jīng)濟損失原因眾多，但國家工業(yè)規(guī)劃布局失誤，調(diào)控措施不力和公民環(huán)保意識不強是主要原因。
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