18

(a) 3

(b) 6

(c) 2

(d) 4

(e) l

⑴5

4

on the move now

over-use of water in the area

misuse or over-use of the land

from deserts can have a dramatic effect on weather systems

new water sources

the management of water supplies

trees and grasses

plants, less water

swallow up

4 (存疑)

1 Clearly the desert is on the move. This is the process experts call desertification.

2 Too many wells are dug. Moreover,什is not enough water or rain to fill reservoirs ・

3 The soil dries out and is then blown away.As a result, the grazing land is destroyed ・

4 Ultimately, it's not only the farmers and villagers who suffer.

5 The fact is, a great deal of work is already under way.

6 The lesson to be leaint lies beneath the sand ・ For example, more than three hundred ancient cities were swallowed up by the desert hundreds of years ago.

Unit 3

2

(b)

3

1 The conventional idea is that all animal intelligence really just results from the animals 9 blind repetition of a particular behaviour.

2 The monkeys touched the pictures on the screen in order, i.e., one square, two trees, three

Unit 2

2

Paragraph 1一2

Paragraph 2一1

Paragraph 3—4 Paragraph 4—3 Paragraph 5—6 Paragraph 6—5

3

Kb) 2(b) 3(c) 4(b) 5(d) 6(b)