So far nobody has claimed the money in the library.
A. discovered
B. to be discovered
C. discovering
D. having discovered
网友回答
(答案→)A. discovered
B. to be discovered
C. discovering
D. having discovered
解析：考虑被修饰词与非谓语动词的主被动和时间关系。the money与 discover之间为被动关系且为过去，故为discovered. to be discovered为将来的被动，discovering为主动进行。Having discovered为主动。