듣던

In a sentence

• 듣던 음악이 끝났다.

  The music I was listening to has ended.

  In this sentence, '듣던' is used before '음악' to describe the music that was being listened to at some previous point.

• 듣던 이야기의 결말을 알고 싶었어요.

  I wanted to know the ending of the story I had been hearing.

  Here, '듣던' modifies '이야기', indicating the story that one was in the process of hearing earlier.

• 그가 듣던 강의는 매우 흥미로웠다.

  The lecture he was attending was very interesting.

  In this example, '듣던' describes the lecture, framing it as one where the listening occurred in the past or previous experience.