一聚未到白首eRd一别已是经年eRd
[yī jù wèi dào bái shŏu erd yī bié yĭ shì jīng nián erd]
'Meeting didn't last till old age; a parting became many years.' This conveys the melancholy realization that one brief meeting was fleeting, while the separation turned into a long absence.