4 · The written style
Because, in writing: -(으)므로
a logical reason in formal texts
-(으)므로 gives an objective reason in notices, documents and formal writing.
-(으)므로 means “because, since” and belongs to writing: notices, instructions, official letters, reports and academic texts. After a vowel or l it is -므로 (가므로, 만들므로 — the l stays), after another consonant -으므로 (있으므로, 많으므로). The past goes inside: -았/었으므로. After a noun it is 이므로: 공휴일이므로.
The reason it gives is presented as a fact or a logical step, not as a personal feeling: 바닥이 미끄러우므로 조심하십시오, “the floor is slippery; please take care”. Unlike -아서/어서, it may be followed by a request or an instruction, which is why notices use it so much.
There is a famous spelling trap. -(으)므로 sounds exactly like a verb turned into a noun with -(eu)m and followed by the particle 으로, which means “by (doing)”, usually with 써: 꾸준히 연습함으로써 실력이 늘었다, “by practising steadily, my skill improved”. Ask whether the clause gives a reason (오므로) or a means (노력함으로써); even Korean writers have to stop and think.
In conversation the same reason is given with -(으)니까, -아서/어서 or -기 때문에. -(으)므로 in speech sounds like someone reading out a regulation.
The form
| after a vowel | 오다 → 오므로 |
| stem ending in l | 만들다 → 만들므로 |
| after a consonant | 있다 → 있으므로 |
| in the past | 바뀌었으므로 |
| after a noun | 공휴일이므로 |
| not to be confused with: by practising | 연습함으로써 |
The rules one by one
The form this topic is about
After a vowel or l use -므로; after another consonant -으므로.
이 약은 졸음을 일으킬 수 있으므로 운전 전에는 복용하지 마십시오.This medicine may cause drowsiness; do not take it before driving.
The reason is objective, so the ending suits notices, documents and reports.
그는 이 분야의 전문가이므로 그의 의견을 들을 필요가 있다.He is an expert in this field, so his opinion should be heard.
Unlike -아서/어서, it may be followed by a request or an instruction.
바닥이 미끄러우므로 조심하십시오.The floor is slippery; please take care.
The past goes inside: -았/었으므로.
회의 장소가 바뀌었으므로 확인하시기 바랍니다.The venue of the meeting has changed, so please check it.
Do not confuse it with the noun form plus 으로써, “by doing”.
비가 많이 오므로 경기를 연기한다.The match is postponed because of the heavy rain.
A closer look
Four ways to say “because”
-아서/어서 is the plain, everyday cause, and it cannot be followed by a request. -(으)니까 gives a reason the speaker wants the listener to accept and happily takes a request. -기 때문에 stresses that this is the reason, in speech and writing alike. -(으)므로 is the written, impersonal one.
A notice on a door might therefore say 공사 중이므로 출입을 금지합니다, while a person standing at the same door would say 공사 중이니까 들어가시면 안 돼요. Both are correct; each belongs to its medium.
How to spot it
- -므로
- -으므로
- 이므로
- -았/었으므로
- 따라서
Example sentences
오늘은 공휴일이므로 도서관은 문을 열지 않습니다.Today is a public holiday, so the library is closed.
공사 중이므로 다른 길을 이용해 주십시오.Construction work is in progress; please use another route.
그는 성실하므로 믿을 만하다.He is conscientious, so he can be trusted.
신청자가 많았으므로 마감을 앞당겼다.There were many applicants, so the deadline was brought forward.
물은 생명에 꼭 필요하므로 아껴 써야 한다.Water is essential to life, so it must be used sparingly.
아이들이 노는 곳이므로 천천히 운전하십시오.Children play here; drive slowly.
8 more example sentences
이 지역은 겨울에 눈이 많이 오므로 겨울용 타이어가 필요하다.It snows a lot in this region in winter, so winter tyres are needed.
자리가 한정되어 있으므로 미리 예약하시기 바랍니다.Places are limited, so please book in advance.
날씨가 추우므로 따뜻한 옷을 준비하십시오.It is cold, so please bring warm clothes.
이 지역은 공기가 깨끗하므로 휴양지로 인기가 많다.The air in this region is clean, so it is popular for holidays.
그 길은 좁고 위험하므로 밤에는 다니지 않는 것이 좋다.That road is narrow and dangerous, so it is best not to use it at night.
제출 기한이 지났으므로 신청을 받을 수 없습니다.The deadline has passed, so we cannot accept the application.
이 제품은 열에 약하므로 햇빛이 드는 곳에 두지 마십시오.This product is sensitive to heat; do not leave it in direct sunlight.
위 사람은 성적이 우수하므로 이 상을 수여한다.This award is presented to the above person for excellent results.
Worth knowing (1)
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By doing: the noun form plus 으로써
The look-alike is a verb turned into a noun with -(eu)m, plus 으로써, “by means of”. It names a method, not a cause, and it can always be paraphrased with English “by …ing”.
꾸준히 연습함으로써 실력을 키울 수 있다.You can build up your skill by practising steadily.
The trap English speakers fall into
Watch out
Both spellings are pronounced the same, omeuro. A reason (“because it is raining”) takes the ending -(으)므로. The noun form with 으로 is for a means and is normally followed by 써: 노력함으로써, “by making an effort”.
A reason is -(eu)meuro; a means is -(eu)m-euro-sseo.
Your turn
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