Act of 1871 expired
May 10, 2014 · When the person you speak to clearly is much older than you. An elderly person, for example. When speaking with your teacher/professor/boss. When you meet someone for the first time and it’s not clear who’s older. When you are unsure. Use 안녕하세요(an-nyeong-ha-se-yo) in that case. In a presentation.