According to a study over 7 years by Professor Kim and members of Professor Kang's team at Korea University, it was ........"그러나(but)". FYI, as for....... noun ----- "사람(a person)" verb ----- "하다(to do)" adjective ----- "없다(there is no... or don't have .....)" adverb ---- "더(more)" interjection ---- "참(oh,well,what,how)" (For example, what a pity!,how beautiful it is, etc.) ^____^

There's too many thing write here I'll tell you some conjuctions 은/는, 이/가, 을/를 maybe these are the most common conjunctions It has something in common. A word just before the conjunction has 'batchim' like '책(book)', in this case use conjunction start with 'ㅇ' like '은', '이', '을' but it has no 'batchim' like '지우개(eraser)', you can use '는', '가', '를' Ex) 나는 책을 샀다 (i'm buy a book) 남동생이 지우개를 잃어버렸다 (my brother is lost an eraser)