something happenedLiterally, “a matter occurred.” 일이 일어나다 means “for something to happen” or “for an incident to occur.” The example sentence uses the related form 일이 일어나고 있소, meaning “What is happening?” or “Something is happening,” in an old-fashioned or formal style.
KO: 어젯밤에 집에서 이상한 일이 일어났어요.
EN: Something strange happened at home last night.