那个花开不败的夏天那些一区不复返的瞬间
[nèi gè huā kāi bù bài de xià tiān nèi xiē yī qū bù fù făn de shùn jiān]
Refers to a specific, unforgettable summer when memorable or unrepeatable moments occurred. A metaphor for cherishing good times that are gone but will never fade.