哭着看我们曾经的照片笑着看我们曾经的回忆
[kū zhe kàn wŏ men céng jīng de zhào piàn xiào zhe kàn wŏ men céng jīng de huí yì]
'Crying over the photos taken in our past together while smiling as I recall what happened between us'. This expresses a mixed sentiment of sadness and nostalgia for a past experience, especially in terms of previous romances, and a bittersweet reminiscence.