This is the 6689th most frequent Korean word.
유씨는
"유씨는" means "Mr./Ms. Yoo is" or "As for Yoo," depending on context.
In this sentence, '유씨는' refers to the person named Yoo, whose actions are being inquired about. The suffix '는' is a particle used for marking the subject in Korean.
유씨는 언제 이곳에 왔나요?
When did Mr./Ms. Yoo come here?
Here, '유씨는' identifies the person named Yoo, and serves as the subject who is described as being kind.
유씨는 아주 친절한 사람입니다.
Mr./Ms. Yoo is a very kind person.
Although '유씨' appears differently in this sentence as '유씨가,' it maintains the subject position in the action of preparing the presentation. The particle '는' could be used as well to place focus on Yoo.