Yeah, ∼운지, ∼은지, ∼는지, ∼한지, ∼을지, ∼울지, ∼할지, ∼건지, ∼려는지, ∼있는지. There are some other things like that. Sounds complicated? It's basically about ‘∼지’. So you need to understand the rule and see how they combine with ‘∼지’ through some examples. Usually, you can combine ‘ㅇ은’ or ‘ㅇㅇ운’ or ‘ㅇㅇ한’-shaped adjective with ‘지’. 좋은 good → 어떤 게 좋은지 모르겠습니다. I don't know which one is good. 밝은 bright → 어떤 게 더 밝은지 모르겠습니다. I don't know which one is brighter. 검은 black → 어떤 게 더 검은지 모르겠습니다. I don't know which one is blacker. 우스운/웃긴 funny → 뭐가 우스운지/웃긴지 모르겠습니다. I don't know what's funny. 귀여운 cute/pretty → 그게 왜 귀여운지 모르겠습니다. I don't know why it's pretty. 따뜻한 warm → 여기는 왜 늘 따뜻한지 모르겠습니다. I don't know why it's always warm. 행복한 happy → 그를 만날 때마다 왜 행복한지 모르겠습니다. I don't know why I'm happy whenever I meet him. There are some adjectives not allowed to combine with only ‘지’. 미친 crazy → 그게 왜 미친 건지 모르겠습니다. I don't know why it's crazy. ∼는지 usually go with the basic form of a verb or the past tense of a verb, and 다 is removed. So 생겼다 became 생겼는지 in the example, because 생겼다 is the past tense of ‘생기다’. 먹다 eat ; 그 맛없는 샌드위치를 다들 왜 먹는지 모르겠습니다. I don't know why people eat the sandwich doesn't taste good. 만들다 make ; 어떻게 만드는지 모르겠습니다. I don't know how I make it.

∼을지, ∼울지, ∼할지 You can recognize the difference through the following examples. 어떤 게 좋은지 모르겠습니다. I don't know which one is good. 어떤 게 좋을지 모르겠습니다. I don't know which one will be good. Ughh, it's a time when I start getting confused now. ∼건지(∼것인지 in written Korean) 왜 그런 일이 생겼는지 모르겠습니다. I don't know why it has happened. 왜 그런 일이 생긴 건지 모르겠습니다. 〃 There's no difference between them. Just two way of saying it. ∼려는지 : 하려는지 going to do / 자려는지 going to sleep 선배가 절 불렀는데 무슨 말을 하려는지 모르겠습니다. My senior called me, I don't know what he's going to say to me. (*하다 do has many meanings.) ∼있는지 거기에 뭐가 있는지 모르겠습니다. I don't know what's over there. 뭘 할 수 있는지 모르겠습니다. I don't know what I can do. Hope this helps.