He was mad at in the English exam.A. failB. droppingC. failingD. lose

问题补充：

He was mad at in the English exam.

A. fail

B. dropping

C. failing

D. lose

答案：

A. fail

B. dropping

(答案→)C. failing

D. lose

解析：fail失败，不及格；drop使降低，终止，落下；lose失败，遗失。在英语考试中不及格，令他很愤怒。本句中at是介词，后面接名词或者动名词作宾语，结合语境可知选C。