B）从Ａ、Ｂ、Ｃ、Ｄ四个选项中，选出可以填入空白处的最佳答案。
6. — Mike got “F” in his history test．
— _________? He has been working so hard on it．
A. How come B. So what C. What for D. Why not
7. _________ is often the case with elder people, my grandma talked about my new hairstyle for at least 50 minutes nonstop．
A. That B. Which C. As D. It
