—How do you improve your listening skill, Mary?—I often do it tapes and English radios.A.

—How do you improve your listening skill, Mary?
—I often do it tapes and English radios.
A. by hearing
B. in listening to
C. by listening to
D. for listening

A. by hearingB. in listening to(答案→)C. by listening toD. for listening解析：考查固定结构。By doing sth通过某种方式或手段。Listen是不及物动词，后跟宾语是要和to连用。所以选C。

我好好复习下