To rack one's brains; to ponder deeply and painstakingly; to be immersed in arduous contemplation.
他为了解决这个技术难题，困心衡虑了好几个夜晚
He racked his brains for several nights trying to solve this difficult technical problem.
Next Idiom
To rack one's brains; to ponder deeply and painstakingly; to be immersed in arduous contemplation.