3 · Sentence endings with attitude
It looks like: -나 보다 and -(으)ㄴ가 보다
a conclusion drawn from evidence
A guess built on something you can see or have heard, usually about somebody else: “they must be …”.
Verbs, 있다 and 없다, and every past form take -나 보다: 오나 봐요, 먹나 봐요, 맛있나 봐요, 왔나 봐요. Adjectives and nouns in the present take -은가 보다, with only an n after a vowel: 좋은가 봐요, 바쁜가 봐요, 학생인가 봐요. A stem in rieul loses it before the n: 살다 → 사나 봐요, 길다 → 긴가 봐요. 보다 is a separate word, so there is a space before it.
The pattern draws a conclusion from evidence. The street is wet, so 비가 왔나 봐요, “it must have rained”. A colleague keeps yawning, so 피곤한가 봐요, “she must be tired”. English says “must”, “seems to”, “I guess”, or “apparently”. The evidence is often said in the sentence before.
It is narrower than 것 같다. 것 같다 can carry a guess, an opinion or your own feeling; -나 보다 only carries a conclusion from evidence, and so it is not used for what you know first-hand. After tasting the soup yourself, 맛있나 봐요 is wrong — you would only say it on seeing other people go back for more.
Used about yourself, it means you are judging from the outside: 제가 많이 피곤했나 봐요, “I must have been really tired” — said after falling asleep on the bus. The guess itself stays in the present, 봐요; anything past is marked before -나. In speech you will also hear -나 보다 after adjectives (바쁘나 봐요), but -은가 보다 is the form that is always safe.
The form
| verb | 오다 → 오나 봐요 |
| verb, past | 오다 → 왔나 봐요 |
| 있다 and 없다 | 맛있다 → 맛있나 봐요 |
| adjective | 바쁘다 → 바쁜가 봐요 |
| after a noun | 학생인가 봐요 |
| adjective, past | 바쁘다 → 바빴나 봐요 |
The rules one by one
The form this topic is about
Verbs, 있다/없다 and every past form take -나 보다.
옆집에 손님이 왔나 봐요.The neighbours seem to have visitors.
Adjectives and nouns in the present take -은가 보다.
민수 씨가 요즘 많이 바쁜가 봐요.Minsu must be very busy these days.
The guess rests on something you have seen or heard.
줄이 정말 길어요. 저 식당이 유명한가 봐요.Look how long the queue is. That restaurant must be famous.
About yourself, it means judging from the outside.
제가 너무 피곤했나 봐요. 버스에서 잠이 들었어요.I must have been really tired. I fell asleep on the bus.
A closer look
-나 보다 or 것 같다?
After watching a film, 재미있는 것 같아요 is your own opinion: “I think it's good”. 재미있나 봐요 would mean you had not seen it — you saw people coming out of the cinema laughing.
So 것 같다 works in both situations and -나 보다 only in the second. It is also not used in questions or for your own plans: whatever you intend, you know, and there is nothing to deduce.
Exceptions and special cases (1)
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you hear -나 보다 after an adjective (바쁘나 봐요, 예쁘나 봐요)
it is common in speech, but -은가 보다 is the form that is right everywhere, in writing as well.
요즘 일이 많이 바쁜가 봐요.Work must be very busy these days.
The two forms go back to two old question endings, one for verbs and one for adjectives, and speech is slowly merging them.
How to spot it
- -나 봐요
- -았나 봐요
- -은가 봐요
- 인가 봐요
Example sentences
길이 젖었어요. 밤에 비가 왔나 봐요.The road is wet. It must have rained in the night.
아기가 계속 울어요. 배가 고픈가 봐요.The baby keeps crying. It must be hungry.
민지 씨가 오늘 기분이 좋은가 봐요. 계속 웃어요.Minji must be in a good mood today. She keeps smiling.
사무실에 불이 꺼져 있어요. 다들 퇴근했나 봐요.The office lights are off. Everyone must have gone home.
저 사람 한국 사람인가 봐요. 한국어를 정말 잘해요.That person must be Korean. Their Korean is really good.
이 집 빵이 맛있나 봐요. 항상 사람이 많아요.The bread here must be good. There are always lots of people.
8 more example sentences
전화를 안 받아요. 지금 운전 중인가 봐요.She isn't answering. She must be driving.
눈이 빨개요. 어제 잠을 못 잤나 봐요.Your eyes are red. You can't have slept last night.
요즘 그 노래가 인기가 많은가 봐요. 어디서나 들려요.That song must be very popular at the moment. You hear it everywhere.
수진 씨가 이 근처에 사나 봐요. 매일 걸어서 와요.Sujin must live near here. She walks in every day.
밖이 시끄러워요. 무슨 일이 있나 봐요.It's noisy outside. Something must be going on.
이 책이 꽤 어려운가 봐요. 다들 힘들어해요.This book must be fairly difficult. Everyone is finding it hard.
두 사람이 많이 친한가 봐요. 항상 같이 다녀요.Those two must be close. They're always together.
제가 길을 잘못 들었나 봐요.I must have taken a wrong turn.
Worth knowing (1)
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The past goes before -나
The guess is always in the present: 봐요. What happened in the past is marked on the verb before it — 왔나 봐요, “someone must have come” — never 오나 봤어요, which would mean “I looked to see whether someone was coming”.
택배가 왔나 봐요. 문 앞에 상자가 있어요.The parcel must have come. There's a box at the door.
The trap English speakers fall into
Watch out
You tasted it yourself, so there is nothing to conclude. -나 보다 is for what the evidence suggests; your own experience takes a plain statement, or -네요 when it is a fresh discovery.
Use na bwayo for what the evidence suggests, not for what you know first-hand.
Your turn
8 exercises on this topic. Your answers are checked in the browser; none of them leaves your device.