왜 그랬는지

why someone did that

→ 왜

phrase Rare #16,823

why someone did that Used in an embedded question about the reason for a past action or behavior. The subject is understood from context, and it often appears with 모르다 (not know) or 궁금하다 (be curious).

KO: 그가 왜 그랬는지 아직도 모르겠어요.

EN: I still don't know why he did that.

제가 왜 그랬는지 모르겠어요

I don't know why I did that.

— 400번의 구타 (1959)

그래요, 우리가… 왜 그랬는지 나도 몰라요

Yeah, I... I don't know why we did that either.

— 영원 (2025)

왜 그랬는지 모르겠어

I don't know why I did that.

— 가장 따뜻한 색, 블루 (2013)

내가 왜 그랬는지 모르겠어

I don't know why I did that.

— 애시 (2025)