As this is his first time to Beijing,he is where to go for a visit.
A. unable for
B. sure about
C. uncertain about
D. uncertain for
网友回答
A. unable for
B. sure about
(答案→)C. uncertain about
D. uncertain for
解析：A、D两项搭配不对，be sure about“对……有把握”;be uncertain about“对……不肯定”，符合句意。