问题补充：
—Mike got “F” in his history test．
一? He has been working so hard on it．
A. How come
B. So what
C. What for
D. Why not
答案：
(答案→)A. How come
B. So what
C. What for
D. Why not
解析：考察交际用语，从答语中“他一直努力学习历史”，选A。How come何以会，为什么表示惊讶So what 即使这样，那又怎么样吗？What for为什么；Why not为何不呢？
