【正确答案】
A
【答案解析】[听力原文] 29-31
Beginning in the 1960s, American women started entering jobs and work positions that had been taken over almost completely by men. In the 1970s, another pattern appeared in work choices: men began entering jobs and work positions held before by women. When John Smith started in nursing school nine years ago, his father took it hard. "Here is my father, a steelworker, hearing about other steelworkers' sons who were becoming soldiers and miners, or getting baseball money to pay for school costs," Mr Smith remembers. The thought of his son becoming a nurse was too much. Today, Mr Smith, an official nurse, earns about $ 30,000 a year at the New Town Hospital in Brooklyn, New York. His father, he says, has changed his mind. Now he tells his fellow workers that their sons, who can't find jobs after four years of college, should have become nurses.
29. What is the passage mainly about?