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Conditional Conjunctions

Quick Reference

-아/어야: only if, must (strong necessity)

  • 가다 → 가야
  • 먹다 → 먹어야

-거든: if/when, since (casual condition/reason)

  • 가다 → 가거든
  • 먹다 → 먹거든

-는 한: as long as, insofar as (limited scope)

  • 가다 → 가는 한
  • 먹다 → 먹는 한

Detailed Explanation

Conditional conjunctions express various types of conditions, from strong requirements to limited circumstances. Each has distinct nuances that affect meaning.

-아/어야

Formation

Pattern: Verb/Adjective stem + -아/어야

Contraction rules (same as -아/어요):

Stem Vowel Suffix Example
ㅏ, ㅗ -아야 가다 → 가야
Other vowels -어야 먹다 → 먹어야
하다 -해야 하다 → 해야

Special cases: - 오다 → 와야 - 되다 → 돼야 - 보다 → 봐야

Meaning and Usage

Core meanings:

  1. Only if: Must do A to achieve B
  2. Must: Strong necessity or requirement
  3. Should: Strong recommendation

Structure: 

A-아/어야 B
(Only if A, then B / Must A to B)

Key characteristics:

  • Strong condition: More emphatic than simple -(으)면
  • Necessity: Implies requirement, not just possibility
  • Common in speech: Used in daily conversation

When to use:

  • Expressing requirements
  • Giving strong advice
  • Stating necessary conditions
  • Explaining prerequisites

Examples

Necessity (must):

  1. 열심히 공부해야 합격해요. (You must study hard to pass.)

  2. 매일 운동해야 건강해져요. (You must exercise daily to become healthy.)

  3. 일찍 일어나야 해요. (You must wake up early.)

  4. 돈을 모아야 여행할 수 있어요. (You must save money to be able to travel.)

Requirements (only if):

  1. 표를 사야 들어갈 수 있어요. (Only if you buy a ticket can you enter.)

  2. 18세가 돼야 운전할 수 있어요. (You can drive only if you're 18.)

  3. 비밀번호를 알아야 열 수 있어요. (You can open it only if you know the password.)

  4. 회원이어야 사용할 수 있습니다. (You can use it only if you're a member.)

Strong advice (should):

  1. 감기에 걸렸으면 쉬어야 해요. (If you caught a cold, you should rest.)

  2. 약속 시간을 지켜야 해요. (You should keep appointment times.)

  3. 선생님 말씀을 들어야 해요. (You should listen to what the teacher says.)

With negation (-지 않아야, -면 안 돼):

  1. 늦지 않아야 해요. (You must not be late.)

  2. 거짓말하면 안 돼요. (You must not lie.)

-거든

Formation

Pattern: Verb/Adjective stem + -거든

No variation: Always -거든 regardless of final consonant.

Type Formation Example
All verbs Stem + -거든 가다 → 가거든
All adjectives Stem + -거든 좋다 → 좋거든
있다/없다 있거든, 없거든 있다 → 있거든

Meaning and Usage

Core meanings:

  1. If/When (condition): Casual hypothetical
  2. Since/Because (reason): Explaining reason
  3. Command + if: Do this, and if/when...

Key characteristics:

  • Casual tone: Used in informal speech
  • Multiple uses: Condition, reason, or sequence
  • Often with commands: V-거든 (if you do)

Context matters: Meaning depends on sentence structure.

Usage 1: Conditional (if/when)

Pattern: A-거든 B (If/When A, then B)

Examples:

  1. 시간이 있거든 놀러 오세요. (If you have time, come visit.)

  2. 배가 고프거든 먹어. (If you're hungry, eat.)

  3. 힘들거든 쉬어. (If you're tired, rest.)

  4. 궁금한 게 있거든 물어봐. (If you have questions, ask.)

  5. 필요하거든 전화해. (If you need it, call me.)

Usage 2: Reason (since/because)

Pattern: A-거든(요) (Because A / Since A)

Often ends the sentence, explaining the preceding statement.

Examples:

  1. 못 가요. 바쁘거든요. (I can't go. Because I'm busy.)

  2. 좋아해요. 맛있거든요. (I like it. Because it's delicious.)

  3. 사야 돼요. 필요하거든요. (I have to buy it. Because I need it.)

  4. 일찍 자요. 피곤하거든요. (I go to bed early. Because I'm tired.)

  5. 안 먹어요. 배가 안 고프거든요. (I'm not eating. Because I'm not hungry.)

Usage 3: Command + Condition

Pattern: Command + -거든 (Do this, and if...)

  1. 가거든 전화해. (If you go, call me.)

  2. 만나거든 안부 전해 줘. (If you meet them, give my regards.)

  3. 사거든 나도 사 줘. (If you buy it, buy one for me too.)

-는 한

Formation

Pattern: Verb stem + -는 한

Verb Type Rule Example
Action verb Stem + -는 한 가다 → 가는 한
Past Stem + -은/ㄴ 한 간 한
Negative -지 않는 한 가지 않는 한

Note: Not commonly used with adjectives.

Meaning and Usage

Core meaning: "As long as," "insofar as," "to the extent that"

Structure: 

A-는 한 B
(As long as A, B / Insofar as A, B)

Key characteristics:

  • Limited scope: Condition applies within limits
  • Formal tone: More common in writing
  • Continuity: As long as condition persists

When to use:

  • Setting limits or boundaries
  • Expressing continuity conditions
  • Formal or written contexts

Examples

Continuous condition:

  1. 살아 있는 한 희망이 있어요. (As long as you're alive, there's hope.)

  2. 노력하는 한 성공할 수 있어요. (As long as you make an effort, you can succeed.)

  3. 건강한 한 일할 수 있어요. (As long as you're healthy, you can work.)

  4. 법을 지키는 한 문제없어요. (As long as you follow the law, there's no problem.)

Within limits:

  1. 내가 아는 한 그는 정직해요. (As far as I know, he's honest.)

  2. 기억하는 한 그랬어요. (As far as I remember, that's how it was.)

  3. 할 수 있는 한 도와드릴게요. (I'll help you as much as I can.)

  4. 가능한 한 빨리 갈게요. (I'll go as quickly as possible.)

Negative conditions:

  1. 포기하지 않는 한 실패하지 않아요. (As long as you don't give up, you won't fail.)

  2. 비가 오지 않는 한 갈 거예요. (As long as it doesn't rain, I'll go.)

Comparing Conditional Conjunctions

Pattern Strength Formality Common Meaning
-아/어야 Strong Neutral must, only if
-거든 Casual Informal if, since
-는 한 Bounded Formal as long as
-(으)면 Basic Neutral if, when

Example comparison:

Topic: Going if weather is good

  1. -(으)면: 날씨가 좋으면 갈 거예요. (If the weather is good, I'll go.)
  2. -아/어야: 날씨가 좋아야 갈 거예요. (Only if the weather is good will I go.)
  3. -거든: 날씨가 좋거든 가. (If the weather's good, go.)
  4. -는 한: 날씨가 좋은 한 갈 거예요. (As long as the weather is good, I'll go.)

Practice

Choose the correct conditional conjunction:

  1. 열심히 _ 성공할 수 있어요. (공부하다 - must study to succeed)

  2. 시간이 _ 전화해 줘. (있다 - if you have time)

  3. 노력하_ 결과가 있을 거예요. (하다 - as long as you try)

  4. 18세가 _ 투표할 수 있어요. (되다 - only if 18+)

  5. 못 가요. 바쁘_. (바쁘다 - because I'm busy)

Fill in with -아/어야, -거든, or -는 한:

  1. 매일 운동_ 건강해져요. (You must exercise daily)

  2. 배고프_ 먹어. (If you're hungry, eat)

  3. 살아 있_ 희망이 있다. (As long as you're alive)

  4. 표를 _ 들어갈 수 있어요. (사다 - must buy ticket)

  5. 필요하_ 말해. (If you need it, tell me)

Show Answers 1. 공부해야 2. 있거든 3. 하는 한 4. 돼야 5. 거든요 6. 해야 7. 거든 8. 는 한 9. 사야 10. 거든