Listening to loud music at rock concertscaused hearing loss in some teenagers.A. isB. areC

问题补充：

Listening to loud music at rock concertscaused hearing loss in some teenagers.

A. is

B. are

C. has

D. have

答案：

A. is

B. are

(答案→)C. has

D. have

解析：本题考查主谓一致。本题考查动名词短语作主语，故谓语动词用单数，根据句意用现在完成时，选C。句意：在摇滚音乐会听大声的音乐已经使得一些青少年的听力受损。