했던 거야

did (it)

→ 하다
phrase Uncommon #11,581
did (it) A conversational past-tense form used to explain or ask about something someone did. The exact English translation depends on the verb phrase before it.
KO: 네가 먼저 시작했던 거야?
EN: Were you the one who started it?

근데 어디 가려고 했던 거 야?

So where were you planning to go?

— Wonderland (2024)

무슨 짓을 했던 거 야?

What did you do?

— 히든 (2005)

왜 아버지는 죽어야 했던 거 야?

Why did my father have to die?

— 극장판 귀멸의 칼날: 무한성편 (2025)

항상 죽이려 했던 거 야

You were always trying to kill me.

— 대부 (1972)

할 일을 했던 거 야.

I did what I had to do.

— 조조 래빗 (2019)