题目内容：
The world’s urban population, (1)____at four times the rate of rural populations, will double in the period 1990 - 2025, to over five billion. Consequently, (2)___
of the people of the world will live in cities, some of (3)____
will be huge. Moreover, about 90% of the growth will be in developing countries. This growth, adding around 60 million people per year (4)____
city populations, will be mainly in Southeast Asia and Africa. The consequences are dramatic. This is change on a scale never before (5)____
, bringing with it considerable challenges and opportunities.
Why does this growth happen? Most of it results (6)____
internal migration rather than the international movement of people, and is caused by a variety of push and pull factors.
One push factor is due to pressure (7)____
land availability. Improved health brings population growth, causing people to move out of rural areas. Others move because of climate change or poor farming methods which often result in deforestation and flooding. Such changes can alter the social structure, leading people (8)____
move. Furthermore, civil war or regional conflicts also cause disruption, driving people out of rural areas.
On the other hand, there are the pull factors. Cities attract people because of the demand (9)____
labour in the manufacturing and service industries. As a result, they offer a higher standard of living (10)____
the lucky ones. Cities also tend to offer greater personal freedom.
…
1 A. increase B. increasing C. increased D. to increase
2. A. two-three B. second-third C. two-thirds D. second-thirds
3. A. which B. that C. what D. whom
4. A. with B. on C. to D. and
5. A. experience B. experienced C. to experience D. experiencing
6. A. on B. in C. to D. from
7. A. at B. on C. for D. with
8. A. move B. to moving C. to move D. moved
9. A. for B. on C. with D. at
10. A. with B. for C. on D. to
参考答案：