It's a good thing that (expressing relief): 기에 망정이지

V + 기에 망정이지 expresses relief at having avoided a negative outcome. It is often combined with conditional patterns 안 했더라면… 을 것이다 (‘if I hadn’t… I would have’) or 안 했더라면… 을 뻔했다 (‘if I hadn’t… I almost certainly would have’):

버스 아니라 지하철로 집에 갔기에 망정이지 안 했더라면 교통에 막힐 거예요.

It’s a good thing that we took the subway instead of the bus — if we didn’t we’d be stuck in traffic.

열심히 공부를 했기에 망정이지 준비 안 했더라면 시험에 떨어질 뻔했어요.

It a good thing that we studied hard because otherwise we’d have almost certainly failed the test.

물병들을 가졍왔기에 망정이지 지금은 너무 더워서 안 했더라면 목이 마를 거예요.

It’s a good thing that you brought water bottles otherwise we’d be really thirsty because now it’s really hot.

돈을 저축했기에 망정이지 안 했더라면 비행기표를 못 살 뻔했어요.

It’s a good job that we saved up otherwise we couldn’t have afforded the plane tickets.

저에게 전화를 했기에 망정이지 안 했더라면 학교에 지각할 뻔했어요.

It’s a good thing that you called me otherwise I’d have been late for school.

휴대폰을 충전했기에 안 했더라면 식당을 못 찾을 뻔했어요.

It’s a good job you charged your phone or we’d never have found that restaurant.

지도를 가져왔기에 망정이지 인터넷 연결을 못해서 길을 잃어버릴 뻔했어요.

It’s a good job you brought a map since there’s no internet connection — otherwise we’d have been lost.