不知不觉青春被校服带走了
[bù zhī bù jué qīng chūn bèi xiào fú dài zŏu le]
'Bu Zhi Bu Jue Qing Chun Bei Xiao Fu Dai Zou' meaning 'Without realising, youth has been carried away by the school uniform'. It expresses that adolescence seems to have slipped past unnoticed in daily routines (e.g., studies) and uniformity, a common sentiment among young people feeling time passing swiftly.