-거든요

you see, because (giving a reason the listener doesn't know)

Level 2 · TOPIK I · beginner

How to use it

Gives a reason or background the listener didn't know, in casual polite conversation. Also brings up a topic before continuing (제가 다음 주에 이사하거든요. 그래서 …).

Forming it

가다	→ 가거든요
바쁘다	→ 바쁘거든요
학생	→ 학생이거든요
먹었다	→ 먹었거든요

Only in conversation, not in writing or formal speeches. It ends a sentence; it doesn't link two clauses.

Examples

아까 밥을 많이 먹어서 배가 부르거든요.
I ate a lot earlier, so I'm full.
제가 다음 주에 이사하거든요. 그래서 좀 도와줄 수 있어요?
I'm moving next week, you see. So could you help me a little?

Compared with similar patterns

-잖아요 gives a reason the listener already knows; -(으)ㄴ/는데요 sets up background and waits for a reaction; -거든 without 요, in the middle of a sentence, is a different pattern meaning 'if'.