问题
选择题
—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
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？