-는 거죠?
ask for an explanation within a shared frame
Form
Verb + -는 거죠?; adjective + -(으)ㄴ 거죠?; noun + 인 거죠?
Function
The construction asks for an explanation or information while framing the situation as already shared or as something that calls for an interpretation. With a wh-word such as 무슨, -죠 cannot be reduced to “right?”: 무슨 일이 … 거죠? means “What exactly is going on?”
Why this form?
-는 거예요? — “what is happening? / is it that…?”: keeps the explanatory -는 것이다 framing but asks more openly and neutrally.
-나요? — “is…? / what…?”: a polite, gentle question without the same sense that the speaker is trying to fit the explanation to an already observed situation.
confirmation -죠? — “right? / isn’t it?”: with a yes/no proposition, -죠? can check information the speaker already assumes; with 무슨 here, the expected answer is information, not yes/no.
Forms not to confuse
-는 거예요?
지금 무슨 일이 일어나고 있는 거예요? — What is happening right now?
-나요?
지금 무슨 일이 일어나고 있나요? — What is happening now?
confirmation -죠?
학생이죠? — You’re a student, right?
Examples
무슨 일이 일어나고 있는 거죠? — What exactly is going on?
왜 문이 잠겨 있는 거죠? — Why exactly is the door locked?