cudgel one 's brains for
As a Chinese idiom, Pinyin is sh ē ns ī K ǔ Su ǒ, meaning to rack one's brains and think hard. It comes from Shi sou Wai Bian er by Hu Yinglin of Ming Dynasty.
explain
Rack your brains and think hard.
source
In the second edition of shisou · waibian written by Hu Yinglin in Ming Dynasty, it is said that "the good sentences of Lingyun are full of deep thought."
cudgel one 's brains for
I know only one, but I don't know the other - zhǐ zhī qí shān,bù zhī qí èr
domestic trouble and foreign invasion - nèi yōu wài huàn
A moth that grows up by accumulating errors - jī é chéng dù
look forward with eager expectancy - yǎn chuān cháng duàn