Many a student wearing MP3 players while walking on the street．It’s quite dangerous．
A. is used to
B. are used to
C. was used to
D. were used to
网友回答
(答案→)A. is used to
B. are used to
C. was used to
D. were used to
解析：考查主谓一致和时态。Many a加单数名词作主语时，谓语动词用单数，排除B,D；根据句子，指的是一般的情况，要用一般现在时态，所以选A。