问题补充：
--- Bob，are you free at the moment？I have to ask you some questions.
--- .
A. It’s a pleasure
B. Ask，please
C. Help yourself
D. Yes，go ahead
答案：
A. It’s a pleasure
B. Ask，please
C. Help yourself
(答案→)D. Yes，go ahead
解析：考察交际用语.根据上文,鲍勃,你这会儿有空吗?我有些问题要问你.可知选D,是的,说吧!最符合语境.
