练习：
A.As a result, its American origins and roots are often quickly forgotten.
B. But this theory fails to explain why American films, music, and television programs are so popular in themselves.
C. American in origin, informal clothing has become the world’s first truly universal style.
D. The BBC,for example, banned rock and roll until 1962.
E. American food has become popular around the world too.
F. This spirit is variously described as being young and free, optimistic and cnfedent, informal and disrespectful.
标准答案： B,F,A,C,D
