How to address a teacher one knows well (in conversation and emails). Is 亲爱 “dear” ever appropriate?
Can one use 亲爱 "dear" in a letter to a teacher one knows well? In the specific case that triggered this question, the student, who is a male student in his late 20s, is being addressed 亲爱的[name]兄弟 ...
I have sometimes wondered what would be the appropriate way of addressing (fellow) students that are junior to oneself. Given name? Full name? Name + 妹/第? Are there even cases where one can use 哥/兄 ...