问题补充：
Asked suddenly about the matter ,he couldn’tan answer at once.
A. come up with
B. look for
C. put up with
D. answer for
答案：
(答案→)A. come up with
B. look for
C. put up with
D. answer for
解析：come up with“得出答案” look for“寻找” put up with“提出” answer for“负责”根据题意，应该选A.
