--Are you sure you have seen this man?---Yes, I’m quite sure that.
A. that, about
B. /, to
C. of, about
D. about. of
网友回答
(答案→)A. that, about
B. /, to
C. of, about
D. about. of
解析：问句中are you sure+that引导的从句,.意为:你肯定…吗? 答句中的 be not too sure about…意为: 在..方面不太有把握.