누가 준 거죠? The sentence has nothing to down with 준거하다 누가 : who 준 : 주(다) + (으)ㄴ 주다 means "to give" ㄴ is a past tense modifier suffix 거죠 : 거 + 이(다) + 지 + 요 거 is colloquial form of 것(thing) 이다 means "to be" 지 is a intimate ending suffix 요 is honorific ending suffx. 거죠 = 것이지요 = 것이에요 (그것은) 누가 준 거죠? literally means "Is that thing who gave to you?" It means "Who gave it to you?" 누가 준 거죠? is a euphemistic expression 누가 줬어요? Peresent tense : 누가 주는 거죠? Who gives it to you? Future tense : 누가 줄 거죠? Who will give it you you? Refer to https://www.italki.com/question/275077 https://www.italki.com/question/367371