一直向后退退不到回忆一直向前走走不出思念
[yī zhí xiàng hòu tuì tuì bù dào huí yì yī zhí xiàng qián zŏu zŏu bù chū sī niàn]
It could be seen as a metaphor for someone trapped in painful memory: When they step back into recollection, it does not comfort their heart; when they go ahead towards happiness, it's hard to let go of yearning