What' s the population of the USA according to the text（）

单项选择题Young people are very important in the USA in that（）

A．many of them will soon be in charge of the country
B．older people are always trying to understand them
C．they are active and interesting
D．they always make trouble in families

单项选择题College students today （）

A．make up nearly halt' of the American population
B．are deeply interested in making a better life for all people
C．have not been given a fair chance before now
D．are always finding fault with their parents