Wǒmen yào tòngdìng-sītòng, xīqǔ zhècì shìgù de jiàoxùn.
We must soberly reflect on this accident and take its lessons to heart.
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From Han Yu's (韩愈) Tang-dynasty letter 《与李翱书》: 如痛定之人,思当痛之时 - like one whose pain has eased looking back on when it hurt. Reflection only becomes useful once the heat of the moment has passed.