You can write sentences about the passage of time and nostalgia for the past. For example

1. Missing the past is like a dead leaf falling to the ground, and the sadness that lies across it is full of unfeeling.

2. In the old days, there was an old city. In a certain old site in the city, there lived old people, humming old songs, guarding the old sunshine, and thinking about an old man.

3. I like myself now, and I miss us in the past.