【答案解析】[听力原文] Effects of Education Studies going back over half a century seem to show that attending college in the US affects political attitudes, usually in a liberal direction./ The changes in political attitude tend to persist beyond the end of college./ No one is entirely certain why college has the effect it does, but the attitudes and role of the faculty are surely an important part of the explanation./ Professors are more liberal than members of other occupations;/ professors at the most prestigious schools are more liberal than those at less celebrated ones;/ professors in the social studies are more liberal than those in engineering or business,/ and younger faculty members are more liberal than older ones./ At one time, the liberalizing effect of college had only a limited impact on national policies because so few people were college graduates./ With more and more young people receiving higher education, college has become, along with the family, an important source of political opinion for the American public.