题目内容：
阅读材料，回答题。Man cannot go on increasing his number at the present rate. In the next 30 years man will faca period of crisis. Some experts believe that there will be a widespread food___ 51 ____. Other experthink this is too pessimistic (悲观的), and that man can prevent things from___ 52 ____worse tha they are now. But remember that two thirds of the people in the world are under-nourished or stmving now.
One thing that man can do is to limit the___ 53 ____of babies born. The need for this is obvious but it is not easy to achieve. People have to be___ 54 ____to limit their families. In the countries of the population___ 55 ____, many people like big families. The parents think that this makes a bigger income for the family and ensures there will be someone in the family who will look___ 56 ____them in old age.
Several governments have___ 57 ____birth control policies in recent years. Among them are Japan, China, India and Egypt. In some cases the results have not been successful. Japan has been an___ 58____The Japanese adopted a birth control policy in 1921~3. People were___ 59 ____to limit their families. The birth rate fell from 34.3 per thousand per year to about 17.0 per year___ 60 ____ present.
________ A．Need
B．want
C．Absence
D．shortage
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