A、About seven million. B、Half of the American population. C、25% of American people. D、About 25 million. A短文提到，“目前美国约有700万在校大学生”，

Millions of words have been written about young people in the United States. There are reasons for this great interest in the ideas, feelings, and actions of youth.
    Today there are about seven million Americans in colleges and universities. Young persons under twenty-five make up nearly half of the American population. Many of these will soon be in charge of the nation. Naturally their ideas are important to everyone in the country, and it is necessary for older people to understand what they think and feel.
    College students today have strong opinions about right and wrong. They are deeply interested in making a better life for all people, especially for those who have not been given a fair chance before now. They see much that is wrong in the lives of their parents. It is hard for them to see what is right and good in the older way. As a result, there is often trouble in American families. Your country may be meeting such problems, too.
22. How many Americans are there in colleges and universities?
23. Why do older people need to understand the ideas of young people according to the passage?
24. What are college students deeply interested in?
25. What is the opinion of American young people about the lives of their parents?