[填空题]Within the next 50 years, population in Africa will rise to 2,000 million, and 1,000 million in South Asia.

[填空题]Within the next 50 years, population in Africa will rise to 2,000 million, and 1,000 million in South Asia.

[单项选择]This instrument, _____and operating next year, will consist of three telescopes.
A. completed
B. completing
C. to complete
D. to be completed

[填空题]Until about two million years ago, Africa’s vegetation had always been controlled by the interactions of climate; geology, soil, and groundwater conditions; and the activities of animals. The addition of humans to the latter group, however, has increasingly rendered unreal the concept of a fully developed "natural" vegetation—i.e., one approximating the ideal of a vegetational climax.
(16)
Early attempts at mapping and classifying Africa’s vegetation stressed this relationship. sometimes the names of plant zones were derived directly from climates. In this discussion the idea of zones is retained only in a broad descriptive sense.
(17)
In addition, over time more floral regions of varying shape and size have been recognized. Many schemes have arisen successively, all of which have had to take views on two important aspects, the general scale of treatment to be adopted, and the degree to which human modification is to be comprehended or

[填空题]

Until about two million years ago Africa’s vegetation had always been controlled by the interactions of climate; geology, soil, and groundwater conditions; and the activities of animals. The addition of humans to the latter group, however, has increasingly rendered unreal the concept of a fully developed "natural" vegetation-- i. e. , one approximating the ideal of a vegetational climax. (41) _____________________. Early attempts at mapping and classifying Africa’s vegetation stressed this relationship: sometimes the names of plant zones were derived directly from climates. In this discussion the idea of zones is retained only in a broad descriptive sense.

(42) _____________________. In addition, over time more floral regions of varying shape and size have been recognized. Many schemes have arisen successively, all of which have had to take views on two important aspects: the general scale of treatment to be adopted, and the degree to which human

[单项选择]

The first 50 years of the next millennium will be critical for the world’s population. By 2050 population growth should have leveled off, but by then we’ll have 10 billion people -- two-thirds as many again as we have today. The rate of population growth is something we can choose right now, though it’s not something that just happens, but a matter of human choice. The choice is a complicated one, with many variables, but it remains a choice.
If we want to prevent a population explosion, we should take action now -- or assist the poorer countries to do so. They need better government, better institutions, better labor and capital markets, better schools.
Anything that increases the value of women’s time and adds to the cost of caring for a child makes a woman less likely to have that child. Since big families are often seen as safety nets for illness and old age, improving poor people’s access to insurance, pensions and welfare instit
A. raising a child is very valuable so far as her time is concerned
B. more children can reduce the cost of raising them
C. the cost for caring for a child is worthwhile
D. the care for a child does not cost her much