열렸던

In a sentence

• 공원이 몇 주 전에 열렸던 적이 있어요.

  The park was opened a few weeks ago.

  Here, '열렸던' functions as an adjective indicating the state or event of the park being opened in the past.

• 문이 열렸던 순간이 내게 매우 놀라웠어요.

  The moment the door opened was very surprising to me.

  In this sentence, '열렸던' is used as part of a descriptive clause modifying '순간', referring to the specific moment the door opened.

• 그곳은 사람들이 떠난 후 열렸던 상당히 아름다운 장소입니다.

  That place, which opened after people left, is a quite beautiful location.

  Here, '열렸던' provides additional context about the time and condition under which the opening occurred.