Think Korean grammar is confusing yet? Just wait. Here’s one of my favorite grammar patterns — Vst + 거든. What does it mean? Well, that depends. Because the pattern 거든 has two very different meanings, one completely unrelated to the other. Luckily for us, when listening to or reading Korean we can easily tell the difference between the two meanings because one is used as a conjunction (in the middle of a sentence) and one is used as a sentence-final verb (at the end of a sentence).
When 거든 is used as a conjunction it means “if” or “when” and sets up a conditional statement. In this regard it’s a lot like the patterns -(으)면 and -다가는. But the unique thing about 거든 is that it’s almost always followed by a proposition or command.
혹시 서울에 오거든 전화 하세요.
If you by any chance come to Seoul, please call me.
그 시험에 합격하거든 나 한테 알려 줘.
If you pass the test let me know.
When 거든(요) is used as a sentence-final ending it sort of functions like an exclamation and means “you know” or “you see”. It also implies a causal connection, so sometimes it can be translated as “because”. It can be used with both present and past tense (었거든), and it can be used with action verb stems, descriptive verb stems, and nouns.
가: 김치 왜 안 먹어? (Why don’t you eat kimchi?)
나: 매운 음식 싫어하거든. (I hate spicy food, you know.) or (Because I don’t like spicy food.)
1년 뒤에 내가 헤어지자고 했거든.
I broke it off after a year, you know.
네 걱정을 많이 했거든요.
We were really worried about you, you know.
Now, there just so happens to be one more usage of 거든 which is much more limited. You can use 거든 in the sentence-final position when you want to introduce a new topic of conversation or some piece of information that the listener is not yet aware of. In this regard, it also functions a lot like the English phrase “you know”.
I got a tattoo!
가: 어제 명동에 갔거든요. (You know, yesterday I went to Myeong-Dong.)
나: 그런데요? (Really?)
가: 응, 거기서 친구를 우연히 만났어요. (Yep, and I ran into a friend there.)