-(으)므로

-(으)므로 gives a reason in formal or written Korean: "because / since …, therefore …".

이유·원인Reason & cause

Han: 써 attaches only to the noun form -(으)ㅁ + 으로 ("by means of"); -(으)므로 is a reason ending and never takes 써.

Examples

이 지역은 강수량이 많으므로 벼농사에 적합하다.This region gets a lot of rainfall, so it is suitable for growing rice.

바닥이 미끄러우므로 걸을 때 조심하시기 바랍니다.The floor is slippery, so please be careful when walking.

내일은 공휴일이므로 도서관이 문을 열지 않습니다.Tomorrow is a public holiday, so the library will be closed.

그는 지난 5년 동안 성실하게 일했으므로 승진할 자격이 충분하다.He has worked diligently for the past five years, so he fully deserves a promotion.

A/V+(으)므로 (vowel stem or ㄹ-stem + 므로, consonant stem + 으므로)

A/V past+았/었으므로

N+이므로

많다 → 많으므로, 크다 → 크므로, 만들다 → 만들므로, 했다 → 했으므로, 공휴일 → 공휴일이므로

It belongs to formal registers: reports, essays, news, notices, speeches. In everyday conversation it sounds stiff; use -아서/어서 or -(으)니까 instead.
Past tense goes before it (-았/었으므로), unlike -아서/어서, which does not take a past marker.
It only connects clauses and cannot end a sentence; to put the reason at the end, use -기 때문이다.
Do not add 써: "-므로써" does not exist. "By means of" is -(으)ㅁ으로써.

Wrong: ~~매일 운동하므로써 건강을 지켰다.~~

Right: 매일 운동함으로써 건강을 지켰다.

써 attaches only to the noun form -(으)ㅁ + 으로 ("by means of"); -(으)므로 is a reason ending and never takes 써.

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