题目内容：

    In an early survey conducted in 1888, a billion and a half people inhabited the earth. Now, the population exceeds seven billion. This means that the world must accommodate a new population roughly equal to that of the United States and Canada every three years. Even though the rate of growth has begun to slow down, most experts believe the population size will still pass eight billion soon.

If we examine the amount of land available for this ever-increasing population, we begin to see the problem. Everyone on the planet had an equal share of land, we would each have about 50,000 square metres. This figure seems to be quite encouraging until we examine the type of land we would have. Not all land is useful to humans as it cannot produce food. We can cut out about one fifth of it because it is permanently covered by snow and ice. Then we can cut out another one fifth because it is desert. Another fifth is too mountainous or is too great a height above sea-level. A tenth doesn’t have enough soil for crops to grow - it is bare rock. Now the position begins to look rather mom bleak (荒凉)!

Obviously, with so little land to support us, we should be taking great care not to reduce it further. But are we? We are consuming its “ capital” , which means its nonrenewable fossil fuels and other mineral deposits that took millions of years to form but which are now being destroyed in decades. We are also doing the same with other vital resources not usually thought of as being nonrenewable such as fertile soils, groundwater and the millions of other species that share earth with us.

The birth of a baby in, for example, Hong Kong, imposes more than a hundred times the amount of stress on the world's resources as a baby in India. Most people in India do not grow up to own cars or air-conditioners. Nor do they eat the huge amount of meat and fish that the Hong Kong child does. Their life-styles do not require vast quantities of minerals and energy. Also, they are aware of the requirements of the land around them and try to put something back into nature to replace what they take out.

1.Why does the author mention the example of America and Canada?

A.To emphasize that world population has to be reduced.

B.To give a brief history of the population growth.

C.To stress how quickly the world population is rising.

D.To point out what a large population they have.

2.According to the author, how much per person of the earths surface can be used to produce food?

A.15,000 square metres. B.25,000 square metres.

C.30,000 square metres. D.40,000 square metres.

3.Which of the following belongs to vital resources?

A.Fossil fuels. B.Mineral deposits.

C.Chemical fertilizer. D.Groundwater.

4.When can learn from the passage that _____.

A.different lifestyles require similar quantities of resources

B.a Hong Kong baby consumes more resources than an Indian baby

C.tropical forest are being better used for pastureland

D.nature is powerful enough to destroy an aggressive man