TOPIK II Grammar · Ch.5 Conditions & Hypotheticals 02

TOPIK II Grammar · Ch.5 Conditions & Hypotheticals 02

'-거든 · -아/어야(만) · -는 한' - Three Strengths of "If"

서울에 도착하거든 연락하세요 - when you arrive in Seoul, get in touch. 약을 먹어야 나아요 - you'll get better only if you take your medicine. 포기하지 않는 한 기회는 있어요 - as long as you don't give up, there's still a chance. English says "if" for all three - Korean gives each condition its own strength.

Key point -거든 = "if / when", but the clause after it must be a command, suggestion, or promise. -아/어야(만) = "only if" - a required condition. -는 한 = "as long as" - formal, mostly written.

How to use it

-거든 means the same as -(으)면, but it can be used in fewer places: the second half has to be a command, suggestion, or promise. 한국에 오거든 꼭 연락해요 (= when you come to Korea, be sure to get in touch). English "if" doesn't care what follows it - -거든 does, and that restriction is the whole rule.

-아/어야 is a required condition - without it, the second half doesn't happen: 표가 있어야 들어갈 수 있어요 (= you can get in only if you have a ticket). You already know this shape from -아/어야 하다 (= have to) - literally "only if you do it, it works". Add 만 - the particle you know as "only" - and the condition becomes even stronger: 노력해야만 얻을 수 있습니다 (= you can gain it only through effort).

-는 한 is the pattern of formal writing and speeches - English "as long as": 건강이 허락하는 한 계속 일하고 싶습니다 (= as long as my health allows, I want to keep working). It often pairs with a negative: 포기하지 않는 한 (= as long as you don't give up).

At a glance

Pattern	Kind of condition	Example
-거든	"if / when" + command·suggestion	필요한 게 있거든 말씀하세요
-아/어야(만)	"only if" - required	서로 이해해야 좋은 친구가 돼요
-는 한	"as long as" (formal·written)	규칙을 지키는 한 문제가 없습니다

Same shape, different use  Sentence-final -거든요 does something else entirely - it gives a reason: "왜 안 가요?" "바쁘거든요." (= "Why aren't you going?" "Because I'm busy.") The conditional -거든 lives only in the middle of a sentence.

Examples

마음에 안 들거든 언제든지 바꾸세요. If you don't like it, exchange it anytime. - condition + command, exactly where -거든 belongs.

여권이 있어야 비행기를 탈 수 있어요. You can board the plane only if you have your passport. - required condition: no passport, no boarding.

제가 여기서 일하는 한 최선을 다하겠습니다. As long as I work here, I'll do my best. - a formal pledge, natural in written or public Korean.

Common mistakes

❌ 봄이 오거든 꽃이 펴요. → ⭕ 봄이 오면 꽃이 펴요. A plain statement - a natural result like flowers blooming - can't follow -거든. If the second half isn't a command, suggestion, or promise, go back to -(으)면.

❌ 열심히 연습해야 대회에서 우승하세요. → ⭕ 열심히 연습해야 대회에서 우승할 수 있어요. -아/어야 is the mirror image of -거든: a command can't follow it. State the result as a possibility (-(으)ㄹ 수 있다) or as a fact.

Quick check

Fill each blank with -거든, -아/어야, or -는 한.

1. 부산에 도착하(      ) 문자 보내 주세요.
2. 비밀번호를 알(      ) 문을 열 수 있어요.
3. 노력을 멈추지 않(      ) 실력은 계속 늘 겁니다.

Show answers

1. 거든 (a request follows, which is exactly where -거든 belongs)   2. 아야 (알아야 - required condition before -(으)ㄹ 수 있다)   3. 는 한 (a general statement follows - "as long as you don't stop")

💡 Study tip - Write one sentence about your own life using -아/어야. Try 실수를 해 봐야 배울 수 있어요 (= you can learn only by actually making mistakes). Say it once tonight, about your own Korean.