为什么i could sense his frustration at not being able to help这里的介词要用at？？

Question

是固定搭配吗？？感觉好别扭。

Answer 1

I could sense his frustration at not being able to help.
这里的介词at是对frustration 的补充，表示无能为力的沮丧。
全句的意思是：
我可以感受到他无能为力的沮丧。
frus‧tra‧tion 发音：. / frʌ'streɪʃ ə n ; frʌˋstreʃən /
英 / frʌ'streɪʃ ə n /
释义： the feeling of being annoyed, upset, or impatient, because you cannot control or change a situation, or achieve something 懊丧，懊恼，沮丧
例句：
People often feel a sense of frustration that they are not being promoted quickly enough.
人们经常有一种挫折感，就是觉得自己升职不够快。
In spite of his frustrations, he fell in love with the country.
尽管失意，但他还是爱上了这个国家。

Answer 2

at表示在某个方面，原文即不能提供帮助这个方面感到慌乱。英语词语的搭配有时是无法讲道理的，只能遵守人家的说话习惯死记硬背。语言学习的本质就是习得一套说话习惯，而不是语法知识。

Answer 3

为您解答
这个没问题的，
Frustration 后面如果跟人，at,with都可以。如果是情况，像这种动名词形式，at没问题的，表示由于某原因而沮丧。