선배들이

In a sentence

• 선배들이 책을 빌려주었어요.

  The seniors lent a book.

  Here, '선배들이' (the seniors) acts as the subject of the sentence.

• 나는 선배들이 가르쳐준 내용을 복습했습니다.

  I reviewed the material that the seniors taught me.

  In this sentence, '선배들이' refers to the seniors who are the doers of the action within the relative clause '가르쳐준'.

• 우리는 선배들이 조직한 행사에 참가할 예정입니다.

  We plan to attend the event organized by the seniors.

  Here, '선배들이' conveys the seniors as the agents who organized the event, modifying '행사'.