Use N + (이)라서 to explain the reason for a particular result -- 'because of N' or 'because/since it's N':
시험기간이라서 대학생들이 열심히 공부를 했어요.
Because of the exam period the university students studied hard.
저는 영국사람이라서 몇몇 한국인이 저의 사투리를 이상한 것 같다고 생각해요.
Because I'm British some Koreans think my accent is strange.
월요일이라서 한국어 수업이 없어요.
I don't have Korean class because it's Monday (today).
설날이라서 비해기표가 더 비쌀 거에요.
Plane tickets will be more expensive because it's Lunar New Year.
공휴일이라서 경기를 취소할 줄 알았어요.
I expected the match to be cancelled because of the national holiday (but it wasn't).**
**