This is the 15320th most frequent Korean word.
백씨는
"백씨는" means "Mr./Ms. Baek" or "Baek [person] is" depending on context.
In this sentence, '백씨는' is used as a subject referring to Mr. Baek, denoting who performed the action of coming to school.
백씨는 오늘 학교에 왔습니다.
Mr. Baek came to school today.
Here, '백씨는' introduces the topic as Mr. Baek, and the sentence describes his characteristics by stating his kindness.
백씨는 매우 친절합니다.
Mr. Baek is very kind.
In this example, '백씨는' identifies Mr. Baek as the person being discussed and leads into information about his activities or state yesterday.