A once-in-a-lifetime opportunity; an extremely rare and precious chance.
能和这位大师面对面交流，真可谓是万世一时，我一定要好好珍惜。
To have the chance to communicate face-to-face with this master is truly a once-in-a-lifetime opportunity; I must cherish it well.
Next Idiom
A once-in-a-lifetime opportunity; an extremely rare and precious chance.