ㄉㄢ ㄐㄧㄥ ㄐㄧˊ ㄌㄩˋ 殚精极虑（殫精極慮） 犹殚思极虑。 明 张居正 《翰林院读书说》：“训誥典謨，圣人岂殫精极虑作意而为之者哉。”
to exhaust one's thoughts and ingenuity (idiom); to think sth through thoroughly; to leave no stone unturned; to rack one's brains
殚(dān)
精(jīng)
极(jí)
虑(lǜ)
