"Today is August 15, 2019. A beam of light passed through a cloud. I remember his name, Yuhui."
"Today is August 27, 2019, and he called me a child."
"Today is October 21, 2019. The books block the sun, but I seem to see him."
…
"Today is December 30, 2020. The cold wind in winter is the tree hole where I hide my heartbeat."
…
"Today is May 9, 2021, classmate Yuhui. Goodbye."
Concept: Ordinary life needs a beam of light