때문이다

In a sentence

• 내가 늦게 온 것은 교통 체증 때문이었다.

  The reason I arrived late was due to traffic.

  In this sentence, '때문이다' indicates the reason or cause for an action described earlier. Here, it explains the reason for being late.

• 행사가 취소된 것은 날씨 때문이라고 들었다.

  I heard that the event was canceled due to the weather.

  The term '때문이다' explains the cause behind an event or occurrence blamed on the weather.

• 그가 성공한 것은 그의 끊임없는 노력 때문이었다.

  His success was due to his relentless efforts.

  Here, '때문이다' identifies the underlying factor for the subject's success, attributing it to consistent effort.