Some of the suspects refused to answer and kept their mouths shut.
A. questioning
B. being questioned
C. questioned
D. to be questioned
网友回答
A. questioning
B. being questioned
(答案→)C. questioned
D. to be questioned
解析：本题是省略的使用。考生可以恢复原句：Some of the suspects(who were)questioned refused to answer and kept their mouths shut．