In many places in China bicycle is still popular means of transportation. A. a; theB. /

问题补充：

In many places in China, bicycle is still popular means of transportation.

A. a; the

B. /; a

C. the; a

D. the; the

答案：

A. a; the

B. /; a

(答案→)C. the; a

D. the; the

解析：自行车，专指大家知道的交通工具，用定冠词表类别；一种。。。方式，固定用法。