flower not flower, Bai ju yi 花非花 白居易

flower not flower, fog not fog,
come mid-night, go day-time.
like a good dream that not last for long,
but a cloud unaware where it goes.

花非花，霧非霧， 夜半來，天明去。
來如春夢幾多時？ 去似朝雲無覓處。