殚精竭虑
dān jīng jié lǜ
to exhaust one's thoughts and ingenuity (idiom); to think sth through thoroughly
to rack one's brains; to leave no stone unturned
ReviewReviewdān jīng jié lǜ
to exhaust one's thoughts and ingenuity (idiom); to think sth through thoroughly
to rack one's brains; to leave no stone unturned