【题目】So far no one has______ convincing evidence of why dinosaurs died out,and it remains a mystery.
A.come about
B.come into
C.come up with
D.come out

【答案】C
【解析】A. come about 形成、产生； B. come into进入；C. come up with想出、提出； D. come out出现、出版。句意：到目前为止，就为什么恐龙灭绝了这个问题还没有人提出一个令人信服的解释，它仍然是个谜。所以答案是C。