rack one 's brains in vain
In Chinese, Pinyin is w ǎ NGF è IX ī NJ ì, which means to waste one's mind. From a dream of Red Mansions.
The origin of Idioms
Chapter 106 of a dream of Red Mansions: "now I've spent all my life in vain, but I've fallen behind."
Idiom usage
It's a waste of time.
rack one 's brains in vain
kindly in appearance but unfathomable at heart - hòu mào shēn qíng
an incompetent man clings to a good position - nú mǎ liàn zhàn dòu
splashing water is like jade beads - fēi zhū jiàn yù