-(으)ㄴ/는 줄 알다/모르다 expresses what you know or don't know to be true, or what you thought was true but wasn't. It conveys awareness or lack of awareness about a fact or situation.
Structure
Verb/Adjective stem + -(으)ㄴ/는 줄 알다/모르다
Breakdown:
- -(으)ㄴ/는: Adnominal ending (modifies 줄)
- 줄: Fact, way (in this context: "the fact that")
- 알다: To know
- 모르다: To not know
Literal meaning: "Know/don't know the fact that..."
Formation Rules
Present Tense with Verbs: -는 줄 알다/모르다
Verb stem + -는 줄 알다/모르다:
- 가다 → 가는 줄 알다 (know [someone] goes/is going)
- 오다 → 오는 줄 알다 (know [someone] comes/is coming)
- 먹다 → 먹는 줄 알다 (know [someone] eats/is eating)
- 하다 → 하는 줄 알다 (know [someone] does/is doing)
- 살다 → 사는 줄 알다 (know [someone] lives)
Present Tense with Adjectives: -(으)ㄴ 줄 알다/모르다
Adjective stem ending in vowel + -ㄴ 줄 알다/모르다:
- 크다 → 큰 줄 알다 (know [it's] big)
- 비싸다 → 비싼 줄 알다 (know [it's] expensive)
- 싸다 → 싼 줄 알다 (know [it's] cheap)
Adjective stem ending in consonant + -은 줄 알다/모르다:
- 좋다 → 좋은 줄 알다 (know [it's] good)
- 작다 → 작은 줄 알다 (know [it's] small)
- 많다 → 많은 줄 알다 (know there are many)
- 적다 → 적은 줄 알다 (know there are few)
Past Tense: -(으)ㄴ 줄 알다/모르다
For both verbs and adjectives:
Stem ending in vowel + -ㄴ 줄 알다/모르다:
- 가다 → 간 줄 알다 (know/knew [someone] went)
- 오다 → 온 줄 알다 (know/knew [someone] came)
- 하다 → 한 줄 알다 (know/knew [someone] did)
Stem ending in consonant + -은 줄 알다/모르다:
- 먹다 → 먹은 줄 알다 (know/knew [someone] ate)
- 읽다 → 읽은 줄 알다 (know/knew [someone] read)
- 듣다 → 들은 줄 알다 (know/knew [someone] heard)
Future Tense: -(으)ㄹ 줄 알다/모르다
Stem ending in vowel + -ㄹ 줄 알다/모르다:
- 가다 → 갈 줄 알다 (know [someone] will go)
- 하다 → 할 줄 알다 (know [someone] will do)
- 오다 → 올 줄 알다 (know [someone] will come)
Stem ending in consonant + -을 줄 알다/모르다:
- 먹다 → 먹을 줄 알다 (know [someone] will eat)
- 듣다 → 들을 줄 알다 (know [someone] will hear)
- 읽다 → 읽을 줄 알다 (know [someone] will read)
Politeness Levels
Formal (합니다체)
- 가는 줄 압니다 (I know [someone] goes)
- 가는 줄 모릅니다 (I don't know [someone] goes)
Polite (해요체)
- 가는 줄 알아요 (I know [someone] goes)
- 가는 줄 몰라요 (I don't know [someone] goes)
Casual (반말)
- 가는 줄 알아 (I know [someone] goes)
- 가는 줄 몰라 (I don't know [someone] goes)
Core Meaning: Awareness vs. Lack of Awareness
줄 알다 - Know that
Being aware of a fact:
- 그가 한국 사람인 줄 알아요 (I know he's Korean)
- 여기가 비싼 줄 알아요 (I know this place is expensive)
- 오늘이 월요일인 줄 알아요 (I know today is Monday)
줄 모르다 - Not know that
Being unaware of a fact:
- 그가 한국 사람인 줄 몰랐어요 (I didn't know he was Korean)
- 여기가 비싼 줄 몰랐어요 (I didn't know this place was expensive)
- 오늘이 월요일인 줄 몰랐어요 (I didn't know today was Monday)
Common Usage Patterns
Mistaken Assumptions (줄 알았다)
Thought something was true but it wasn't:
- 그가 학생인 줄 알았어요 (I thought he was a student [but he's not])
- 여기가 은행인 줄 알았어요 (I thought this was a bank [but it's not])
- 오늘이 금요일인 줄 알았어요 (I thought today was Friday [but it's not])
Discoveries (줄 몰랐다)
Didn't know something but found out:
- 그가 결혼한 줄 몰랐어요 (I didn't know he was married)
- 이렇게 어려운 줄 몰랐어요 (I didn't know it was this difficult)
- 여기가 이렇게 먼 줄 몰랐어요 (I didn't know this place was this far)
Current Knowledge
What you currently know:
- 그가 오는 줄 알아요 (I know he's coming)
- 시험이 내일인 줄 알아요 (I know the exam is tomorrow)
- 그 사실을 아는 줄 알아요 (I know you know that fact)
Special Meaning: Ability (줄 알다/모르다)
Knowing How to Do Something
-(으)ㄹ 줄 알다/모르다 with abilities:
Can do:
- 한국어 할 줄 알아요 (I know how to speak Korean / I can speak Korean)
- 운전할 줄 알아요 (I know how to drive / I can drive)
- 요리할 줄 알아요 (I know how to cook / I can cook)
- 수영할 줄 알아요 (I know how to swim / I can swim)
Cannot do:
- 한국어 할 줄 몰라요 (I don't know how to speak Korean)
- 운전할 줄 몰라요 (I don't know how to drive)
- 요리할 줄 몰라요 (I don't know how to cook)
- 수영할 줄 몰라요 (I don't know how to swim)
Note: This usage with -(으)ㄹ specifically expresses ability/skill.
Tense Conjugations
Present Awareness
Polite: -(으)ㄴ/는 줄 알아요/몰라요
- 가는 줄 알아요 (I know [someone] goes)
- 비싼 줄 알아요 (I know [it's] expensive)
- 가는 줄 몰라요 (I don't know [someone] goes)
Past Awareness/Discovery
Polite: -(으)ㄴ/는 줄 알았어요/몰랐어요
- 간 줄 알았어요 (I thought [someone] had gone)
- 비싼 줄 몰랐어요 (I didn't know [it] was expensive)
- 가는 줄 몰랐어요 (I didn't know [someone] was going)
Future Awareness
Polite: -(으)ㄹ 줄 알 거예요/모를 거예요
- 갈 줄 알 거예요 (I will know [someone] will go)
- 비쌀 줄 알 거예요 (I will know [it] will be expensive)
Common Expressions
About People
- 그가 한국 사람인 줄 몰랐어요 (I didn't know he was Korean)
- 그녀가 선생님인 줄 알았어요 (I thought she was a teacher)
- 그가 결혼한 줄 몰랐어요 (I didn't know he was married)
- 그가 오는 줄 알아요 (I know he's coming)
About Situations
- 이렇게 어려운 줄 몰랐어요 (I didn't know it would be this difficult)
- 이렇게 비싼 줄 몰랐어요 (I didn't know it was this expensive)
- 오늘이 휴일인 줄 몰랐어요 (I didn't know today was a holiday)
- 시간이 이렇게 빠른 줄 몰랐어요 (I didn't know time passed so quickly)
About Places
- 여기가 도서관인 줄 알았어요 (I thought this was the library)
- 여기가 이렇게 먼 줄 몰랐어요 (I didn't know this place was this far)
- 여기가 유명한 줄 몰랐어요 (I didn't know this place was famous)
About Abilities
- 한국어 할 줄 알아요? (Do you know how to speak Korean?)
- 피아노 칠 줄 알아요? (Do you know how to play piano?)
- 운전할 줄 몰라요 (I don't know how to drive)
Negative Forms
Don't Know That (Negative Awareness)
줄 모르다:
- 가는 줄 몰라요 (I don't know [someone] is going)
- 비싼 줄 몰라요 (I don't know [it's] expensive)
줄 알지 못하다:
- 가는 줄 알지 못해요 (I don't know [someone] is going - formal)
Negative Content
Know something is NOT true:
- 안 가는 줄 알아요 (I know [someone] is not going)
- 비싸지 않은 줄 알아요 (I know [it's] not expensive)
- 안 간 줄 알았어요 (I thought [someone] hadn't gone)
Question Forms
Asking About Awareness
Did you know?:
- 그가 한국 사람인 줄 알았어요? (Did you know he was Korean?)
- 여기가 비싼 줄 알았어요? (Did you know this place was expensive?)
- 오늘이 휴일인 줄 알았어요? (Did you know today was a holiday?)
Asking About Abilities
Can you...?:
- 한국어 할 줄 알아요? (Do you know how to speak Korean?)
- 운전할 줄 알아요? (Do you know how to drive?)
- 요리할 줄 알아요? (Do you know how to cook?)
Example Dialogues
Dialogue 1: Discovery
A: 이 식당이 이렇게 맛있는 줄 몰랐어요.
(I didn't know this restaurant was this delicious.)
B: 저도 친구가 추천해 줘서 알았어요.
(I also found out because my friend recommended it.)
Dialogue 2: Mistaken Assumption
A: 오늘 일요일인 줄 알았어요.
(I thought today was Sunday.)
B: 아니에요, 토요일이에요.
(No, it's Saturday.)
Dialogue 3: Ability
A: 한국어 할 줄 알아요?
(Do you know how to speak Korean?)
B: 조금 할 줄 알아요.
(I know how to speak a little.)
Dialogue 4: Current Knowledge
A: 시험이 내일인 거 아는 줄 알아요?
(You know the exam is tomorrow, right?)
B: 네, 아는 줄 알아요. 공부하고 있어요.
(Yes, I know. I'm studying.)
Common Mistakes
❌ Incorrect: 가요 줄 알아요
Using polite form before 줄
✅ Correct: 가는 줄 알아요
Use adnominal form
❌ Incorrect: 좋다는 줄 알아요
Wrong ending for adjectives in present
✅ Correct: 좋은 줄 알아요
Use -(으)ㄴ for present adjectives
❌ Incorrect: 할 줄 알아요 (meaning "know he will do")
Confusing ability with future
✅ Correct: 할 줄 알아요 (means "know how to do")
-(으)ㄹ 줄 알다 = ability
한다는 줄 알아요 (know he does)
Usage Notes
줄 알았다 vs 줄 몰랐다
줄 알았다 (mistaken belief):
- 그가 학생인 줄 알았어요 (I thought he was a student [but he's not])
줄 몰랐다 (discovery):
- 그가 학생인 줄 몰랐어요 (I didn't know he was a student [now I know])
Ability Usage
Only with -(으)ㄹ 줄 알다/모르다:
- 할 줄 알아요 (can do / know how to do)
- 할 줄 몰라요 (can't do / don't know how to do)
Comparison with Similar Expressions
-(으)ㄴ/는 줄 알다 vs -는지 알다
줄 알다 (awareness of fact):
- 그가 가는 줄 알아요 (I know he's going - aware of the fact)
-는지 알다 (knowing whether):
- 그가 가는지 알아요 (I know whether he's going)
-(으)ㄴ/는 줄 알다 vs -다고 알다
줄 알다 (common, natural):
- 비싼 줄 알아요 (I know it's expensive)
-다고 알다 (less common, more formal):
- 비싸다고 알아요 (I know that it's expensive)
Summary Table
| Form | Usage | Example |
|---|---|---|
| -는 줄 알다 | Know (verb, present) | 가는 줄 알아요 |
| -(으)ㄴ 줄 알다 | Know (adj/past) | 좋은 줄 알아요 |
| -(으)ㄹ 줄 알다 | Know (future) / Ability | 갈 줄 알아요 |
| -는 줄 몰라요 | Don't know (present) | 가는 줄 몰라요 |
| -(으)ㄴ 줄 알았어요 | Thought (mistaken) | 학생인 줄 알았어요 |
| -(으)ㄴ 줄 몰랐어요 | Didn't know (discovery) | 비싼 줄 몰랐어요 |
| -(으)ㄹ 줄 모르다 | Don't know how (ability) | 할 줄 몰라요 |
Key Takeaways
- ✅ Expresses awareness: What you know/don't know to be true
- ✅ Uses adnominal forms: -(으)ㄴ/는/ㄹ before 줄
- ✅ 줄 알았다: Mistaken assumptions (thought it was true)
- ✅ 줄 몰랐다: Discoveries (didn't know, now know)
- ✅ Ability meaning: -(으)ㄹ 줄 알다/모르다 = can/can't do
- ✅ Very common: Essential for expressing discoveries and abilities
-(으)ㄴ/는 줄 알다/모르다 is a fundamental pattern in Korean for expressing what you know or don't know, making it essential for natural conversation and expressing discoveries or mistaken beliefs.