曾经的一切只是虚无缥缈
[céng jīng de yī qiè zhĭ shì xū wú piāo miăo]
All That Was Once There is Just Illusory. It shows that the past has become vague and intangible, maybe due to the passage of time or the disappearance of people, objects or feelings, indicating a kind of nostalgia and disillusionment towards the past.