These Korean grammar points are focused on plans and intentions
1)~(으)ㄹ 까 하다: (Uncertain plan) This grammar point shows that the speaker is still wondering if you will do the action or not. So the decision has not been made yet. Note: ~(으)ㄹ까 모르다 and ~(으)ㄹ까 만까하다 ate the same grammar point and mean the same thing.
확실하지는 않지만 다음 주에 경주에 갈까 해요.
방학을 하면 고향에 가까 합니다.
2) ~(으)려던 참이다: (You were about to do something) showing that something moved you away from previous action. This grammar point usual comes with “마침” “안 그래도”. “마침” “안 그래도” place emphasis or coincidence on the fact that you moved to do something else. It can be positive and negative.
마침 쉬려던 참이었어요
안 그래도 병원에서 검사를 받아보려던 참이었어요.
3) ~(으)려다가: (Intended to do). This grammar point shows that you planned to do something but some thing happened so you were unable to do it.
이번 방학에 제주도에 가려다가 일이 생겨서 못 갔어요.
자전거를 피하려다가 넘어져서 다쳤어요.
4) ~(으)ㄹ 뻔하다: (Nearly happened/Nearly finished it). Something seemed to happen but in the end it didn’t happen. Or maybe you nearly finished something but in the end something prevented you from finishing it.
길을 건너다가 사고가 날 뻔 했어요.
늦게 일어나는 바람에 늦을 뻔 했어요.
우리 팀이 이길 뻔했는데 마지막에 졌어요.
5)~기로 하다: (Decide to do something) This Korean Grammar point shows that you have decided to do something.
이번 방학에 고향에 가기로 했어요