Core Grammar Rule: ~는지 알다/모르다
This pattern is used to embed a question about a piece of information into a larger sentence, typically to ask if someone knows (알다) or doesn't know (모르다) that information. It's the Korean equivalent of "Do you know where/what/when/if...".
Meaning & Usage
Meaning: It connects a clause containing a question word (like 언제 when, 어디 where, 누구 who, 무엇 what, 어떻게 how, 왜 why) or an uncertain situation to the verbs 알다 (to know) or 모르다 (to not know).
When to use: Use it when you're not asking a direct yes/no question, but rather asking about the content of the question itself. For example, instead of asking "Is the bank open?" you ask "Do you know what time the bank closes?".
Conjugation Rules
Verbs: Attach ~는지 directly to the verb stem, regardless of whether it ends in a vowel or a consonant.
가다 (to go) → 가는지
먹다 (to eat) → 먹는지
Adjectives: Attach ~(으)ㄴ지. If the stem ends in a vowel, add ~ㄴ지. If it ends in a consonant, add ~은지.
예쁘다 (to be pretty) → 예쁜지
작다 (to be small) → 작은지
Nouns (이다): Attach ~인지 to the noun.
학생 (student) → 학생인지
의사 (doctor) → 의사인지
Verb: ~는지 / Adjective: ~(으)ㄴ지 / Noun: ~인지
Native Nuance & Mistakes
To sound more natural, it's important to use this pattern correctly and avoid common pitfalls, especially regarding politeness and sentence structure.
Use 모르겠어요 instead of 몰라요
Context: When you don't know the answer to a question in a polite conversation, saying 몰라요 can sound a bit blunt or cold. Natives much more commonly use 모르겠어요 or 잘 모르겠어요 (I'm not quite sure). This softens the response and makes you sound more considerate.
Example: "이 근처에 은행이 어디에 있는지 아세요?" (Do you know where a bank is near here?) → "죄송해요. 잘 모르겠어요." (I'm sorry. I'm not sure.) is more natural than "몰라요." (I don't know.)
Don't Confuse with Simple Noun + 알다/모르다
Context: ~는지 알다 is for knowing information about something, not just knowing the thing itself. For example, 민수씨를 알아요? means "Do you know Minsu?". But 민수씨가 어디에 사는지 알아요? means "Do you know where Minsu lives?". A common mistake is to mix these up. You can't say 민수씨가 어디에 살아요 알아요? (X). The question part must be converted into the ~는지 clause.
Example: "Do you know his phone number?" → 그 사람 전화번호를 알아요? (O) / "Do you know what his phone number is?" → 그 사람 전화번호가 몇 번인지 알아요? (O)
Do: 잘 모르겠어요. (O) / Don't: 몰라요. (Can be blunt)
Common Question Words with ~는지
The ~는지 알다/모르다 pattern is most frequently used with question words (interrogatives) to ask about specific pieces of information.
Location & Time
어디 (where): Used to ask about the location of a person, place, or thing.
경회루가 어디에 있는지 아세요? (Do you know where Gyeonghoeru is?)
몇 시 (what time) / 언제 (when): Used to ask about the time of an event.
수문장 교대식은 몇 시에 하는지 알아요? (Do you know what time the Royal Guard Changing Ceremony is?)
Other Information
누구 (who): To ask about a person's identity.
저 분이 누구인지 아세요? (Do you know who that person is?)
왜 (why): To ask for a reason.
친구가 왜 화가 났는지 모르겠어. (I don't know why my friend is angry.)
어떻게 (how): To ask about a method or way of doing something.
어떻게 해야 할지 모르겠어요. (I don't know what to do.)
어디에 있는지? / 몇 시에 하는지?
Answering ~는지 Questions
When someone asks you a question using ~는지 알다/모르다, you can respond in several ways depending on whether you know the information.
When You Know
You can confirm you know and then provide the answer. A simple 네, 알아요 (Yes, I know) followed by the information is common.
Example: (수문장 교대식은 몇 시에 하는지 알아요?) → 그건 알아요. 제가 홈페이지에서 봤어요. (I know that. I saw it on the website.)
When You Don't Know
The most common and polite way to say you don't know is (잘) 모르겠어요.
Example: 지도를 봐도 어디인지 잘 모르겠어요. (Even looking at the map, I'm not sure where it is.)
If the other person also doesn't know, you can add 나도 (me either).
Example: 나도 어디 있는지 모르겠는데? (I don't know where it is either.)
When You're Not Sure
If you have an idea but aren't certain, you can use expressions like 아마 ~일걸요? (It's probably...).
You can also explicitly state your uncertainty with 확실하지는 않아요 (I'm not sure).
Example: (오늘 도서관 몇 시에 닫는지 알아?) → 아마 열 시일걸? (Probably at 10 PM?)
네, 알아요. / 잘 모르겠어요. / 아마 ~일걸요?
Politeness & Formality
The politeness level of this expression is controlled by the ending of the final verb, 알다 or 모르다. You must adjust it based on who you are talking to.
Polite Form (해요체)
Context: Use ~는지 아세요? or ~는지 알아요? when speaking to strangers, older people, or in any formal or semi-formal context. 아세요? is slightly more formal and respectful than 알아요?. For negative answers, 모르겠어요 is much more common and softer than a blunt 몰라요.
Example: 저 분이 누구인지 아세요? (Do you know who that person is?) / 죄송하지만 잘 모르겠어요. (I'm sorry, but I don't really know.)
Casual Form (반말)
Context: Use ~는지 알아? and ~는지 몰라? when speaking with close friends, family, or people younger than you. The structure is the same, but the verb endings change to the casual form.
Example: 우리 내일 어디서 만나는지 알아? (Do you know where we're meeting tomorrow?) / 아니 나도 몰라. (No, I don't know either.)
Polite: ~는지 아세요? / 모르겠어요. / Casual: ~는지 알아? / 몰라.