关于构件的基本应用，下列说法有误的是
A．MenuBar和Menu都没有必要注册监听器，只需要对Menultem添加监听器ActionLis-tener，完成相应操作 javawColor提供了颜色的构造方法Color(int r，int g，int
B．，其中r，g和b代表了三维空间的长、宽和高
C．对话框Dialog是Window类的子类，对话框和一般窗口的区别在于它依赖于其他窗口
D．按钮Button是―个最常用的构件，当按钮被点击后，会产生ActionEvent事件，需Ac-tionListener接口进行监听和处理事件
参考答案：B
解析：解析：java．awt．Color提供了颜色的构造方法Color(int，r,int，B) ，其中r，g和b代表了红绿蓝的0～255之间的整数值。
| 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. |
Which of the following is the best title of this passage
A．How to Keep Balance Between Population and Environment
B．How to Control Population Effectively
C．How to Educate People on Birth Control
D．How to Improve the Poor People’s Lives