—Paul invited us to take part in a party tomorrow evening.
— Is tomorrow his birthday?
A. Why not?
B. What for?
C. That’s all right.
D. What a good idea
网友回答
A. Why not?
(答案→)B. What for?
C. That’s all right.
D. What a good idea
解析：本题的含义是保罗邀请我们参加明天晚上的聚会？为什么邀请什么？明天是他的生日吗？本题用为什么意思较符合，what for可以表示为什么的意思，故本题选B。