好景不常
The morning sun never lasts a day.
The longest day must have an end.
Every day is not Sunday.
A wonder lasts but nine days.

eg：The social disorder destroyed the once prosperous town, the morning sun never lasts a day.

中英俚语俗语来源：王勃·滕王阁序：“好景不常，盛延难再。”

反义词：天下无不散之延席 Merry meet， merry part.