-(으)ㄴ 지 (시간)이 되다/지나다
it has been (time) since
2-daraja · Ibora
Izoh
States how much time has passed since an action. Vowel or ㄹ stems (ㄹ drops) take ㄴ 지, consonant stems 은 지, followed by a time + 되다/지나다/넘다.
Misollar
한국에 온 지 2년이 됐어요.
It's been two years since I came to Korea.
밥을 먹은 지 한 시간도 안 됐어요.
It hasn't even been an hour since I ate.
그 친구를 못 만난 지 오래됐어요.
It's been a long time since I saw that friend.
TOPIK izohi
TOPIK I Reading 43–45, 49–56 (time spans).