Population expansion is one of the most serious problems in the world. With better hygienic conditions and better medical care, fewer babies die today. But the birth rate remains unchanged. Moreover, the death rate has been lowered considerably by various kinds of progress. People generally live longer than they used to. All these contribute to a series of problem: shortage of national resources and food supply crowded cities and high rate of unemployment.

　　To solve all these problems, we must take measures to control birth rate. The first important step is to educate people-to help them understand the advantages of small families. Another important measure is to raise people's living standards. When people full understand the consequences of population expansion, and when their standard of living is raised, the birth rate will decline without compulsion.

　　Though it is a difficult task, we should try in a thousand and one ways to carry out birth control If we fail to do so, the world will be too crowded to live in, and the natural resources will be used up. Then we will no longer survive on earth.