20. “what makes her so unhappy?”

问题描述:

20. “what makes her so unhappy?”
“____ one of her favorite books.”
A. Because she lost B. Because of her losing
C. She lostD. Her losing
正确答案为D,为何不B,请讲解!

WHY 提问才可以用BECAUSE回答
这里是WHAT提问,所以不用BECAUSE