题目内容：

He was mad at her( ) not telling him the truth 填介词

优质解答

for.
He was mad at her for not telling him the truth!
他对她发脾气了,因为她没有跟他讲实话!
第一,be mad at sb对...发脾气 tell sb the truth 告诉...真相
第二,根据句意,介词for在此表原因.
第三,特别注意介词后的动名词,其否定形式是在动名词前直接加not.个人认为这可能是困扰你的原因之一.类似的例句 His boss was mad at her for his being late again.他的老板因为他的再次迟到而发脾气了.