—Would you like me to help you with the maths problem?
— It’s a most difficult one.
A. With pleasure.
B. Why not?
C. That’s all right.
D. It’s my pleasure.
网友回答
A. With pleasure.
(答案→)B. Why not?
C. That’s all right.
D. It’s my pleasure.
解析：考查交际用语：A.With pleasure.很乐意，B.Why not?好啊， C.That’s all right.没关系，D.It’s my pleasure.不用谢，句意：--你想要我帮助你做这个数学题吗？--好啊，这是最难的一题。选B。