Unit 4《Key to exercises in the workbook (I)》课件(新人教选修Ⅸ)25

important to the world?
深圳：刘超英
Suggested answers to Exercise 1:
1 Tropical rainforests occur in three major regions: Asia, Africa and Central and South America.
the world's rainforests. ▪ Tell the government and people around you
that you are against the destruction of tropical rainforests. ▪ Follow the 3 "Rs": reduce, reuse and recycle so that not so much new wood and minerals are needed.
E. Oh really? I didn't know that. Now, could you outline some of the reasons why it's not a good idea to destroy rainforests?
A: Sure. You must have heard about the rich animal and plant life in tropical rainforests. Well, there are about 10 million species of plants and animals in the world. More than half of these live in the tropical rainforests. So, destroying rainforests means that thousands of these species are dying out before we've even realized it.
1 In which parts of the world would you find tropical rainforests?
2 Why do you think rainforests are being cut down?
3 Why do you think tropical rainforests are
world's tropical rainforests have been destroyed, and that's in les5 than 50 years. Over 150 acres of rainforest is lost every minute in Asia, Africa, Central and South American.
① the area of the earth's land covered by
tropical rainforest ③ reasons why rainforests are being
destroyed
② the rate of rainforest destruction ⑤ some consequences of rainforests being
E: So, what can individuals do to help slow down the destruction?
A: That's a good question ... (fade out)
Talking
Suggested answers to Exercise 1: ▪ Buy renewable rainforest products. ▪ Support organisations that are fighting to save
E: I've heard too that the rainforest could provide us with cures for diseases.
A: Yes, there are certainly many new drugs waiting to be discovered. Another problem is that the destruction of foists contributes to global warming. Also, rainforests absorb a lot of rain so that there's a constant supply of clean water running into river and lakes. If the trees are cut down, the rain isn't absorbed and there is flooding.
▪ Listening (First listening)
1 Before you listen to the tape, look at the
pictures. One is of a tropical rainforest and the other is of a tropical rainforest that has been cut down. In groups, answer the questions.
destroyed
④ the best way to make money from
rainforests
3 Now listen again. Are these statements true
or false? Correct the false statements.
1 Rainforests cover 14% of the earth's land surface.
2 As populations increase, people need more land to live on. There are also mining companies which destroy forests in their search for minerals.
3 Because there are about 10 million species of plant and animal in the world. More than half of these live in the tropical rainforests. The rainforest could provide us with cures for diseases. Also, rainforests absorb a lot of rain so that there's a constant supply of clean water running into rivers and lakes.
▪ Second listening
2 Listen to Ed Walker interviewing Dr
Anne Butler about the destruction of tropical rainforests. Number the topics below in the order in which you hear about them.
2 More than half of the rainforests have
√ disappeared.
3 150 acres of rainforest are destroyed every day.
√ 4 In 40 years' time we might not have any
rainforests left on earth.
E: That's unbelievable.
A: Yes, it's frightening. The last remaining rainforests could be gone in less than 40 years.
E: But why is this happening?
A: Well, there are a number of reasons. As populations increase, people need more land to
Reasons why rainforests are being destroyed
Consequences of rainforests being destroyed
•to provide land for people to live on
• to plant crops
• to start farms
live on. Forests an cut down to plant crops or to start farms. The wood is sold for
firewood or building materials, furniture and paper, for example. And there are also mining companies which destroy the forests in their search for minerals.
深圳：刘超英
LISTENING TEXT
THE DESTRUCTION OF
TROPICAL RAINFORESTS
Ed Walker (E) is interviewing Dr Anne Butler (A ) about the destruction of tropical rainforests.
▪ Suggested answers to Exercise 2:
• to make money from firewood
•the loss of thousands of species of plant and animal
• the loss of the opportunity to find new drugs to treat diseases
深圳：刘超英
E: Anne, we hear a lot these days about how quickly tropical rainforests are disappearing.
A: Yes, that's right. Rainforests now cover only 6% of the earth's land surface. They used to cover about 14%, so more than half of the
5 People can make more money from
√ harvesting rainforest plants than from cutting
▪ T4hird listening Listen again. Write notes
under the headings below.
•to sell wood for building materials, furniture and paper • to search for minerals (mining companies)
ቤተ መጻሕፍቲ ባይዱ
•the increase in global warming • flooding ( rain can't be absorbed if there are no trees)
E: I suppose people have to make a living.
A: Yes, but you know, people can make more money by harvesting things like fruits, nuts and oils, as well as plants that can be used in medicine than by cutting down the forests.