I heard a soft at the door. When I looked up I found it was Mary. A. noiseB. soundC. voi

问题补充：

I heard a soft at the door. When I looked up, I found it was Mary.

A. noise

B. sound

C. voice

D. cry

答案：

A. noise

B. sound

(答案→)C. voice

D. cry

解析：

soft可以用来形容声调的柔和，因此应选voice。