입구에

In a sentence

• 입구에 사람이 많이 모여 있었어요.

  There were many people gathered at the entrance.

  입구에 is used to specify the location where people are gathered, indicating a place or position.

• 우리는 입구에 도착하자마자 한 명씩 체크인을 했습니다.

  As soon as we arrived at the entrance, we checked in one by one.

  입구에 here describes the place of arrival upon which the action of checking in takes place.

• 그 행사는 입구에 안내 표지가 잘 보이게 놓여 있었습니다.

  At the entrance of the event, the sign was placed clearly visible.

  입구에 describes the location where the sign is placed, emphasizing visibility at that location.