【单选题】听力原文: In the past few years, millions of Americans have become suddenly enthusiastic about the bicycle as if it were a great new invention. Annual bicycle sales doubled between 1960 and 1970, and ther...
【简答题】Millions have become members of health clubs and have _____________ health club one of the fastest growing business in the US today. And now the beneficial effects of these changing attitudes and beha...