单选题 It would be wise if you had not breathed a single word of the matter.
A. would be wiser B. would have been wiser
C. would have been wise enough D. can be wiser

【正确答案】 B
【答案解析】在虚拟的条件句，其动词既可用完成时，也可用不定式。另外，因为该句是个虚拟句，所以wise应以比较级的形式出现。