曾经的那段青春如此深刻曾经的那段青春如此怀念
[céng jīng de nèi duàn qīng chūn rú cĭ shēn kè céng jīng de nèi duàn qīng chūn rú cĭ huái niàn]
It describes how profoundly impacting and nostalgic a certain period of one's youth was. Youth has been experienced with great depths, leading it becoming deeply missed as times passes.