Goodbye Yi Chengyan

This was the first time I saw him. At that time, I thought he was a teacher in school, because I had never seen a boy wearing such a formal shirt before, and I could never think of him except a teacher. At the age of 15, I was still shy, a girl who would blush casually, so I never thought of going up to say hello or asking for contact information, not to mention that at that time I thought he was a teacher. This is the first time I see him after many years of separation...