Mistake is temporary regret, but missing is eternal regret.
Hence,the eternal regret could not be avoided that the West-Route-Army did not finish the important task of meeting the Communist International but was defeated in the Qilian Mountains.
In this secular and emotional time, I can only sigh, Wuyama Oonwoo, entangled the eternal regret of life.
A sea of eternal regrets1
One single slip brings eternal regret, and looking back, your whole life has passed away.
Too much too late, in hesitation, waiting, hesitation become eternal regret.