问题补充：
—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.
答案：
A. With pleasure.
(答案→)B. Why not?
C. That’s all right.
D. It’s my pleasure.
解析：说话者是主动地向对方提供帮助,那么,对方的答语只能是B项,表欣然同意。A项意思是I’ll do that with pleasure或I’m glad to do that。C项表“没关系、不客气”与对话的逻辑意义不符。D项表乐意地为某人做过了某事。
