a hard nut to crack
US /ə hɑrd nʌt tu kræk/
UK /ə hɑːd nʌt tu kræk/
成语
一个难题, 一个难缠的人
a problem that is difficult to solve or a person who is difficult to understand or deal with
示例:
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This math problem is really a hard nut to crack.
这个数学问题真是一个难题。
•
My boss is a hard nut to crack; he rarely changes his mind.
我的老板真是个难缠的人；他很少改变主意。