Guesses something from what you see or hear: 불이 꺼졌어요. 자나 봐요 (buri kkeojyeosseoyo. jana bwayo), "The lights are off. They must be asleep".
Checked against the official learner dictionary from the National Institute of Korean Language
- Verbs, adjectives ending in 있다/없다, and anything with 았/었 take 나 보다 (or 는가 보다, which sounds more written).
- Other adjectives take (으)ㄴ가 보다: 바쁜가 봐요 bappeunga bwayo. Nouns take 인가 보다.
Build it
When to use it
Guessing from what you see
A clue, then the guess.
Guessing about the past
With 았/었.
Realizing about yourself
Noticing something in hindsight.
Watch out
After a noun it has to be 인가 보다.
In context
8 examples- 1
불이 꺼졌어요. 다들 자나 봐요.
Buri kkeojyeosseoyo. dadeul jana bwayo.
The lights are off. Everyone must be asleep.
- 2
줄이 길어요. 이 식당이 유명한가 봐요.
Juri gireoyo. i sikdangi yumyeonghanga bwayo.
There's a long line. This restaurant must be famous.
- 3
길이 젖었네요. 밤에 비가 왔나 봐요.
Giri jeojeonneyo. bame biga wanna bwayo.
The road is wet. It must have rained last night.
- 4
사람이 많네요. 맛있나 봐요.
Sarami manneyo. masinna bwayo.
It's packed. The food must be good.
- 5
전화를 안 받아요. 바쁜가 봐요.
Jeonhwareul an badayo. bappeunga bwayo.
They're not answering. They must be busy.
- 6
우산을 쓴 걸 보니 비가 오나 봐요.
Usaneul sseun geol boni biga ona bwayo.
People have umbrellas, so it must be raining.
- 7
저 사람이 선생님인가 봐요.
Jeo sarami seonsaengniminga bwayo.
That person must be the teacher.
- 8
아이가 계속 울어요. 배가 고픈가 봐요.
Aiga gyesok ureoyo. baega gopeunga bwayo.
The kid keeps crying. They must be hungry.
Practice
6 questions자다 + 나 봐요
나 보다 or 아/어 보다?
They look alike but have nothing to do with each other. 아/어 보다 a/eo boda means "try": 먹어 봐요, "try it". 나 보다 is a guess: 맛있나 봐요, "it must be good". The giveaway is the form before 보다: 먹어 meogeo vs 먹나 meongna.
나 보다 or 는 것 같다?
Both guess. 는 것 같다 neun geot gatda is the general one, and it also works for your own opinion. 나 보다 sounds like you're working it out from a clue you just noticed, which is why it often follows a description of what you saw:
- 이게 더 좋은 것 같아요. "I think this one's better." Your opinion.
- 사람이 많네요. 맛있나 봐요. "It's packed. It must be good." A guess from a clue.
Look it up in the dictionary
The entry for 나 보다 in two trusted Korean dictionaries.