-How do you know that she likes singing?-I often hear herafter class.A. to singB. singingC

问题补充：

-How do you know that she likes singing?

-I often hear herafter class.

A. to sing

B. singing

C. sing

D. sings

答案：

A. to sing

B. singing

(答案→)C. sing

D. sings

解析：本题回答语的含义是我经常听到她在课后唱歌，表示结果用hear sb do sth，故本题选C。