"Once the snow falls in Chang 'an, this life will only be remembered, not returned to people" is a poem written by Du Mu in the Tang Dynasty, which depicts a person's emotional loneliness and deep thoughts.
"The snow in Chang 'an once fell" means that the snow in Chang 'an has disappeared, and the "snow in Chang 'an" here means good memories or happy times. The following "Never forget in this life, never give back to others" expresses the poet's nostalgia for the good old days and his feelings for those who are separated from him. By describing the disappearance of snow and the departure of people, the whole poem expresses the poet's longing for the good old days and the people related to them.