To regret a past action or decision, wishing one had foreseen the current negative consequences.
他当初不听劝告，坚持己见，结果投资失利，如今只能早知今日，悔不当初
He didn't heed advice back then, sticking to his own views, and as a result, his investment failed; now he can only regret his past actions, wishing he had known this would happen today.
Era:
Ancient
Frequency:
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