Lesson 82: ~구나, ~군 and ~군요

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Oh! I didn’t realize that…: ~구나, ~군 or ~군요



낚싯줄 = fishing line
둥지 = bird’s nest
암호 = secret code
비만 = obesity
식욕 = appetite
정상 = normal
장마 = rainy season
지필 = pen and paper
생명 = life
생명보험 = life insurance
해군 = navy
대령 = colonel
면 = side/face
표면 = surface
지면 = the ground surface
보도 = sidewalk
선반 = shelf
불안감 = anxiety

가속하다 = to accelerate
감속하다 = to decelerate
칠하다 = to paint
쓰다듬다 = to pet

당황스럽다 = to be embarrassed
불안하다 = to be anxious, to be uneasy

Adverbs and Other Words:
맨 = at the very begging, end, start, finish
얼른 = adverb placed in sentences when speaker wants listener to do something quickly

For help memorizing these words, try using our Memrise tool.



In this lesson you will learn how to add ~구나, ~군 or ~군요 to the end of a sentence.  This grammatical form is often said when one realizes a new fact or piece of information. Allow me to break it down more than that. Let’s get started.



Oh! I didn’t realize that…: ~구나, ~ or ~군요

Just like many of the other grammatical principles that you have learned recently, creating a direct English translation for ~구나, ~군 or ~군요 is difficult. Instead, it is better to understand its usage and the subsequent meaning and feeling that it can create.

Regardless of if it attaches to a verb, adjective or 이다, these endings are added to the end of a sentence that speaker just came to realize.

When adding this to an adjective or 이다, ~구나, ~군 or ~군요 are attached directly to the stem of the adjective (or attached to 이 in the case of 이다). For example:

과학 선생님이구나

Let me explain when and why this phrase would be used.

As I stated earlier, ~구나, ~군 or ~군요 are added to the end of a sentence that the speaker just came to realize. In effect, the speaker is showing surprise of this newly discovered information. A speaker would use one of these endings at the end of a sentence that he/she did not know before. In this situation, the speaker would have just discovered that this person is a Science teacher. For example:

Person 1: 그 사람은 그냥 영어 회화 선생님이 아니야?
= That person isn’t an English teacher?

Person 2: 응. 원래 영어 회화 선생님인데 지금 과학선생님이야
= No, originally he was an English teacher, but now he is a Science teacher

Person 1: 아 진짜? 과학 선생님이구나
= Ah really? I didn’t know/realize he is a science teacher

Let’s look at another example, this time using an adjective.

Imagine you are going to go fishing for the first time. You go to the store to buy supplies, and you see the price of fishing line. You are surprised because you didn’t realize that fishing line is that expensive. In this case, you can say the following:

낚싯줄이 이렇게 비싸구나 = I didn’t know/realize that fishing line is this expensive

Below are more examples. As you may have guessed, ~구나 and ~군 are used in informal situations and ~군요 is used in formal situations. Also, ~구나 is very common in conversation – much more common than ~군. However, younger people commonly use ~군 when chatting on the internet or on their phones.

해군에 대령이군요 = I didn’t realize that you were a general in the navy
네가 매우 똑똑하구나 = I didn’t realize that you are so smart
이 시험이 지필시험이구나 = I didn’t realize that this exam is a pen-and-paper exam
지구 표면은 거의 다 물이구나 = I didn’t realize that most of the earth’s surface is water
생명보험이 그렇게 중요하구나 = I didn’t realize that life insurance was that important
이 돌의 표면이 아주 부드럽구나  = I didn’t realize that the surface of this rock was so soft

보도로 맨 끝까지 걸어갈 수 있구나
= I didn’t realize that you could walk to the very end on this path

미국에서 비만이 아주 큰 문제이구나
= I didn’t realize that obesity was such a big problem in America

햇빛으로 지면이 이렇게 뜨거울 수 있구나
= I didn’t realize that the earth’s surface could get so hot from sunlight

이 전철에 가방을 올려놓을 수 있는 선반이 없군
= I didn’t realize that there was no shelf to put your bag onto on the subway

You have learned many examples where 있다 and 없다 – although adjectives – are treated like verbs when adding some grammatical principle. Notice that when adding ~구나, ~ or ~군요, you treat 있다 and 없다 like adjectives.

Also notice that ~이/가 is used on the subject of these sentences. In Lesson 17, I indicated that one of the purposes of ~이/가 is to denote the subject of a sentence that the speaker just realizes or is experiencing. The nature of the sentences using ~구나, ~군 or ~군요 make it more natural to use ~이/가.

In Lesson 23, you learned about 그렇다 (which is an adjective) and the many ways it can adapt to grammatical principles. ~구나, ~군 or ~군요 are commonly added to 그렇다. This construction is often used when the speaker wants to refer to the previous situation and say “Oh! I didn’t realize that.” For example:

Person 1: 그 친구가 어디 갔어?
= Where did that friend go?

Person 2: 여기가 좀 불안해서 집에 갔어
= He was a little uncomfortable here, so he went home

Person 3: 그렇구나
= Oh… (I didn’t realize that fact)


When adding ~구나, ~군 or ~군요to a verb, ~는 should be placed between it and the verb. For example:

너도 암호를 모르는구나
= Oh, I didn’t realize that you didn’t know the password either

아들이 수영을 잘 하는군요 =
Oh, I didn’t realize that your son is good at swimming

장마에 비가 이렇게 많이 오는구나
= Oh, I didn’t realize that it rains this much during the rainy season

강아지가 쓰다듬는 것을 싫어하는구나
= Oh, I didn’t realize that the dog doesn’t like to be pet

오늘 우리가 그냥 정상 수업을 하는구나
= Oh, I didn’t realize that we are just doing normal classes today


When adding this to a verb, adjective or 이다 in the past tense, you can attach ~구나, ~군 or ~군요 to ~았/었. For example:

벌써 먹었구나
= Oh, I didn’t realize that you already ate

어제 생일이었구나
= Oh, I didn’t realize that yesterday was your birthday

둥지가 나무에서 떨어졌구나
= Oh, I didn’t realize that the nest fell from the tree

수술을 받은 후에 식욕을 잃었구나
= Oh, I didn’t realize that you lost your appetite after the surgery

선생님도 그때 아주 당황스러웠군요
= Oh, I didn’t realize that you were very embarrassed at that time too

학교 앞 표면을 다 초록색으로 칠했구나
= Oh, I didn’t realize that you painted the front surface of the school green


~구나, ~군 or ~군요are used when one realizes something. Inherently, one usually realizes something about a fact that has already happened or is currently happening. However, it is also possible to add ~구나, ~군 or ~군요 to a sentence conjugated to the future tense. This would most commonly be done if one realizes that something will be the case. The realization still happens in the present tense, but the event will happen in the future. These realizations of future events are typically guesses, and therefore you would most commonly see ~겠다 used instead of ~ㄹ/을 것이다. For example:

돈이 없겠구나 = Oh, we will probably not have money
당황스럽겠구나 = Oh, you will probably be embarrassed


Sentences using ~구나, ~군 or ~군요 have a feeling that the speaker is speaking to himself/herself. This “self-talking” isn’t really part of the conversation – the speaker is just kind of mumbling to “Ah, I didn’t realize _______.”

The question is, then, if that were the case, why would we need to use “군요?” Why would we need to use polite speech if this form is used to talk to oneself? Well, you won’t see this is any other grammar book (I don’t think), because this is my personal opinion. I have been exposed to this form (in conversation, books, Korean tests, other writings, etc…) and I have the feeling that sentences before “~구나/~군/~군요” are mostly said to oneself.

I would say that, within one sentence, 90% of the feeling is that the speaker is speaking to himself/herself. The remaining 10% is the speaker wanting to show the listener that he/she is surprised about the fact. Therefore, while technically “self-speech,” a part of the function of the sentence is to show the listener that the speaker is surprised. This is the reason why we should use honorifics if the situation calls for it (if you are speaking to somebody who deserves high respect).

Anyways, that’s just my observation.

That’s it for this lesson!

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