问题
单项选择题
美国心理学家本杰明·布鲁姆研究指出，如果17岁儿童智力为100%成熟的话，那么，儿童4岁时已达到（）。
A.20%
B.50%
C.70%
D.80%
答案
参考答案：B
解析：学前儿童能力发展的特点之一智力发展迅速，本杰明·布鲁姆儿童智力发展曲线：布鲁姆以17岁为发展的最高点，假定其智力为100%，4岁已经发展了50%，故选B。
搜题请搜索小程序“爱下问搜题”
美国心理学家本杰明·布鲁姆研究指出，如果17岁儿童智力为100%成熟的话，那么，儿童4岁时已达到（）。
A.20%
B.50%
C.70%
D.80%
参考答案：B
解析：学前儿童能力发展的特点之一智力发展迅速，本杰明·布鲁姆儿童智力发展曲线：布鲁姆以17岁为发展的最高点，假定其智力为100%，4岁已经发展了50%，故选B。
| 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 institutions also has a major impact. This can be as simple as rural credit, providing a means of saving. Finally, there is education -- both for women and, perhaps even more important, for the next generation of children. These steps are there to be taken, but there appear to be some countries that are not seriously trying at the moment. If we cannot achieve that we will certainly not control population. That said, I don’t feel pessimistic that we are going to run out of resources: we are becoming more efficient at producing food faster than the rate at which population is increasing. There is, however, a risk that we will wreck the environment so effectively that the world will no longer be an attractive place to live. That really would be a dismal outcome, to reach world population equilibrium only to find we’d destroyed the natural environment in the process. |
By the time this article was written, the population of the world was approximately ______.
A．300 million
B．600 million
C．6 billion
D．10 billion