I tried hard to get some information about the new technology out of his mouth, but he remained ．
A. quiet
B. secret
C. silent
D. calm
网友回答
A. quiet
B. secret
(答案→)C. silent
D. calm
解析：本题为四个形容词的区别，quiet为“安静的”，secret为“秘密的”，silent 为“沉默的”，calm为“心情平静的”，故选C项。