如今我丢了纯真的笑脸现在你添了成熟的容颜
[rú jīn wŏ diū le chún zhēn de xiào liăn xiàn zài nĭ tiān le chéng shú de róng yán]
Translated to 'Now I have lost my innocent smile while you now wear a mature expression'. This phrase shows two contrasting life changes over time: loss of innocence and gaining maturity.