To rack one's brains; to think painstakingly and meticulously; to expend extreme mental effort.
为了找到这个难题的解决方案，他常常抠心挖血，反复推敲。
To find a solution to this difficult problem, he often racked his brains, pondering repeatedly.
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To rack one's brains; to think painstakingly and meticulously; to expend extreme mental effort.