--Do you often hear John in his room? --Yes. Listen! Now we can hear him in his room.A.

问题补充：

--Do you often hear John in his room? --Yes. Listen! Now we can hear him in his room.

A. sing; to sing

B. singing; singing

C. sing; singing

D. to sing; singing

答案：

A. sing; to sing

B. singing; singing

(答案→)C. sing; singing

D. to sing; singing

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