Basically, "또" and "다시" are the same, meaning "again". You may have come across "또다시". In this case, "또" is just used to emphasize "다시" in Korean. It would be translated with "once again" or "once more" in English. ex) 그는 <또다시> 실패했지만 실망하지 않았다. (He failed <once more>, but he wasn't disappointed.) <또다시> 이와 같은 일이 일어나지 않도록 하세요. (Make sure that such a thing will not happen <once again>.) --------------------------------------------------------------------------------------------------------- And I wanna tell you another meaning of "또". In this usage, there can be many sentences. But the overall meaning is that you "add something else to something". ex) 무엇이 <또> 필요하세요? (What <else> do you need?) 그 케이크 맛있던데 <또> 남은 거 없어? (I really liked the cake, do you have <any other> cake left over?) 내가 거기에 있었을 때 <또> 이런 일도 있었다. (When I was there, this event <also> happened.> 그거 말고도 <또> 중요한 것은 그 사진이다. (Besides this, what's <also> important is the photo.> ------------------------------------------------------------------------------------------------------------------------------- Explaining the concept of "딱" is not easy, but let me give it a shot by example sentences. 1) exactly 그거 딱 좋아! (That's exactly what I like.) 그 옷들은 나한테 딱 맞아! Those clothes exactly fit me. (So, they are probably too tight on you.) 2) just or only <Imagine that you haven't yet finished your homework and the due date is only 30 minutes away. Then you could beg your teacher to have mercy on you and give you more time to complete it> <딱> 한 시간만 더 주세요. (Please! Give me <just> one more hour!) 3) It is used to stress the very moment when something happens. 내가 몸을 돌리자 <딱> 그 사람과 눈이 마주쳤다. (As I turned around, <it was at that moment that> I met the person's eyes.>