@Dony님: 안녕하세요. 뭔가 오해가 있는 것 같은데 ^^; 뜻만 놓고 봤을 때 그 둘이 다를 게 없다는 뜻이었어요. 제가 볼 때 주로 서울, 경기도 분들이 '-구' 를 쓰시더라고요. I meant "There's no semantic difference between them" by "No semantic difference", not something like "No, there's the semantic difference.". And I agree with you, I also feel more comfortable with -고. Though I use both. @Cynthia: 그렇기도 하구 means "It seems like that". Well, 뭐뭐 하기도 하고 doesn't make a lot of sense, it sounds like a extremely vague expression that only the speaker does know the exact meaning. 좀 그래/그렇다 is a typical one. A : 이 옷 어때? What about this cloth? B : 좀 그렇다. It's kind of like that. Hope it helps!

---------------------------------------------------------- addition. What did I misunderstand? hm...~ 구 is a dialect... I know... but I don't know where's dialect..... I don't know What different meaning between ~구 and ~고....? haha....... Exactly, ~고 must be standard language. isn't it? 혹시 제가 어디서 잘못 이해했는지 알려주시면 감사하겠습니다.*^^*...... Can you tell me what I misunderstood it?^^ I want to know semantic difference between ~고 and ~구....haha^^;;; ----------- 이문제가 틀렸고, 저문제도 틀렸고. 이문제가 틀렸구, 저문제도 틀렸구. 그가 뭐했다고 그러는거야? 그가 뭐했다구 그러는거야? I think ~구 is same ~고.. and I speak thoese..... but..I'm more familiar ~고.

I think, ~고 and ~구 are same meaning and correct. '~고' is standard language. but '~구' is local dialect. so, '~고' is usually used by people although ~구 is correct. Good luck^^

No semantic difference. -구 is a dialect word being spoken in Seoul and cities in Gyeong-gi province.