— What made you so upset?
— the exam.
A. Failing to pass
B. To fail passing
C. Failing passing
D. To fail to pass
网友回答
(答案→)A. Failing to pass
B. To fail passing
C. Failing passing
D. To fail to pass
解析：本题考查动词的-ing形式作主语，完整形式为Failing to pass the exam made me so upset.。fail to do表示“未能做到”。