4. The girl was listenedin the next room when I came back last night.A. to singingB. to si

问题补充：

4. The girl was listenedin the next room when I came back last night.

A. to singing

B. to sing

C. singing

D. Sang

答案：

(答案→)A. to singing

B. to sing

C. singing

D. Sang

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