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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

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出自：国家开放大学-开放英语4

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