Korean has a whole shelf of auxiliary verbs that attach to a main verb's -아/어 form and add a layer of meaning about how or why the action is done — done for someone, tried out, finished off, left in place, stashed for later, or lingering as a state. The main verb carries the lexical content; the auxiliary carries the aspect or attitude. This page is the look-up grid for the six most frequent of them. The glue that binds every row is the same -아/어 connective you already use for the past tense and the 해요체 present — so if you can build 먹어요, you can build 먹어 보다.
The connective is ordinary vowel harmony
Every auxiliary here sits on the -아/어 form of the main verb, chosen by vowel harmony: 아 after a stem whose last vowel is ㅏ or ㅗ, 어 otherwise, and 해 for 하다. Then the auxiliary — not the main verb — takes all the tense, politeness, and negation. Read the grid as [main verb in 아/어 form] + [auxiliary], and conjugate only the auxiliary.
| Pattern | Nuance it adds | Example | English |
|---|---|---|---|
| -아/어 주다 -a/eo juda | benefactive — does the action for someone's benefit | 사 줘요 sa jwoyo | buys it for me |
| -아/어 보다 -a/eo boda | attemptive — tries the action to see how it goes | 먹어 봐요 meogeo bwayo | tries eating it |
| -아/어 버리다 -a/eo beorida | completive — carries it through, done and gone (relief or regret) | 다 먹어 버렸어요 da meogeo beoryeosseoyo | ate it all up |
| -아/어 놓다 -a/eo nota | resultative — does it and leaves the result standing | 문을 열어 놓았어요 muneul yeoreo noasseoyo | left the door open |
| -아/어 두다 -a/eo duda | preparatory — does it in advance and keeps it for later | 표를 사 뒀어요 pyoreul sa dwosseoyo | bought the tickets ahead |
| -아/어 있다 -a/eo itda | resultant state — the subject stays in the state the change produced | 의자에 앉아 있어요 uija-e anja isseoyo | is (sitting) seated |
Benefactive: -아/어 주다
The action is done for someone's benefit. This is also the engine of the everyday polite request -아/어 주세요 — leave the 주다 off a request and a polite ask quietly becomes a bare command.
이것 좀 들어 주세요.
igeot jom deureo juseyo
Could you hold this for me for a second?
친구가 공항까지 데려다줬어요.
chinguga gonghangkkaji deryeodajwosseoyo
My friend gave me a lift all the way to the airport. (for my benefit)
Attemptive vs completive: -아/어 보다 and -아/어 버리다
-아/어 보다 frames the action as an experiment — do it and see. In the past it drifts into "have (ever) done": 가 봤어요 "I've been there." -아/어 버리다 is the opposite mood: the action is pushed all the way to finished and irreversible, with an emotional charge of relief ("phew, dealt with") or regret ("darn, it's gone").
이 김치찌개 한번 먹어 봐요.
i gimchijjigae hanbeon meogeo bwayo
Give this kimchi stew a try.
제주도에 가 봤어요?
jejudo-e ga bwasseoyo?
Have you ever been to Jeju Island? (past = experience)
깜빡하고 그 약속을 잊어버렸어요.
kkamppakago geu yaksogeul ijeobeoryeosseoyo
I completely spaced and forgot about that plan. (regret, done and gone)
Resultative pair: -아/어 놓다 vs -아/어 두다
Both mean "do the action and leave its result in place," and for many everyday physical acts they are interchangeable. The nudge that separates them: 놓다 foregrounds the state existing right here, right now (열어 놓다 "leave it open"), while 두다 foregrounds having stashed it away for later use (사 두다 "buy and keep for later"). With mental verbs — 알아 두다 "learn and keep in mind" — only 두다 sounds idiomatic.
더우니까 창문을 열어 놓았어요.
deounikka changmuneul yeoreo noasseoyo
It's hot, so I've left the window open. (the open state is the point, right now)
이 단어들은 미리 외워 두세요.
i daneodeureun miri oewo duseyo
Memorize these words in advance (and keep them ready). (두다 for later use)
Resultant state: -아/어 있다
With an intransitive change-of-state verb, -아/어 있다 says the change is done and its result still holds — 앉아 있다 "be seated," 문이 열려 있다 "the door is open." Note there is no 고 here: it is the bare -아/어 connective plus 있다. This is the mirror image of the progressive -고 있다, which describes the change unfolding rather than its result.
벽에 그림이 걸려 있어요.
byeoge geurimi geollyeo isseoyo
A painting is hanging on the wall. (걸리다 → 걸려 있다, resultant state)
아직 사무실에 남아 있어요.
ajik samusire nama isseoyo
I'm still at the office. (남다 → 남아 있다)
Where English speakers stumble: it must be -아/어, not -고
These are light-verb aspect markers, and the connective they demand is the harmony vowel -아/어, not -고. English speakers who have learned the -고 auxiliaries (-고 있다, -고 싶다) often carry -고 over by analogy and produce ×먹고 보다 for "try eating." The two connectives are not interchangeable: -고 있다 marks an ongoing action, while -아/어 있다 marks a resulting state, and 보다·주다·버리다·놓다·두다 all take -아/어 exclusively.
Common Mistakes
1. Using -고 where -아/어 is required. The attemptive is 먹어 보다, never ×먹고 보다.
❌ 이거 한번 먹고 보세요.
Wrong — the attemptive auxiliary takes -아/어, not -고: 먹어 보세요.
✅ 이거 한번 먹어 보세요.
igeo hanbeon meogeo boseyo
Try eating this.
2. Conjugating the main verb instead of the auxiliary. Tense and politeness ride on the auxiliary.
❌ 표를 미리 샀어 뒀어요.
Wrong — the past goes on 두다, not on 사다: 사 뒀어요, not ×샀어 뒀어요.
✅ 표를 미리 사 뒀어요.
pyoreul miri sa dwosseoyo
I bought the tickets in advance.
3. Dropping 주다 from a request, turning it into a command. The benefactive is what makes the ask polite.
❌ 문 좀 열어요.
Blunt — without 주다 this reads as a flat 'open the door'; add 주다 for a request.
✅ 문 좀 열어 주세요.
mun jom yeoreo juseyo
Could you open the door, please?
4. Using -아/어 있다 with a transitive/action verb. Resultant-state 있다 pairs with intransitive change-of-state verbs; for an ongoing action use -고 있다.
❌ 지금 밥을 먹어 있어요.
Wrong — eating is an ongoing action, so it's 먹고 있어요, not ×먹어 있어요.
✅ 지금 밥을 먹고 있어요.
jigeum babeul meokgo isseoyo
I'm eating right now.
Key Takeaways
- All six auxiliaries attach to the main verb's -아/어 form (harmony: ㅏ/ㅗ → 아, else → 어, 하다 → 해); the auxiliary carries tense and politeness.
- Nuances: 주다 = for someone, 보다 = try, 버리다 = finish off (relief/regret), 놓다 = leave the result, 두다 = keep for later, 있다 = resultant state.
- 놓다 vs 두다: both "do-and-leave," but 두다 leans "store for later," 놓다 leans "leave it right here"; mental verbs prefer 두다.
- Never swap in -고: it is 먹어 보다, not ×먹고 보다 — and -아/어 있다 (state) is not -고 있다 (ongoing action).
Now practice Korean
Reading grammar gets you part of the way. The exercises are where it sticks — free, no signup needed.
Start learning Korean→Related Topics
- Auxiliaries -고 있다 / -고 싶다 / -게 되다: Reference TableTOPIK 2 — Three of the highest-frequency Korean auxiliaries in one grid: -고 있다 for the progressive 'be ~ing', -고 싶다 for desire 'want to' (which inflects like an adjective), and -게 되다 for the change of state 'come to / end up'.
- Conjugation Sheet: 주다 (give / do for someone)TOPIK 2 — The full look-up sheet for 주다 — the ㅜ-stem that contracts to 줘요 (주 + 어 → 줘) — with the three-way deference split 줘요 / 주세요 / 드려요 and the benefactive auxiliary -아/어 주다 that overtly marks an action as a favour: 도와줘요, 해 주세요, 해 드릴게요.
- Conjugation Sheet: 보다 (see / watch / try)TOPIK 1 — The full look-up sheet for 보다 — the ㅗ-stem that contracts to 봐요 (보 + 아 → 봐) — plus its two other lives: the humble 뵙다/봬요 for meeting a superior, and the everyday auxiliary -아/어 보다 'try doing.'
- -아/어 주다: Doing Something For Someone (and Requests)TOPIK 2 — The benefactive auxiliary -아/어 주다 folds 'for someone's benefit' right into the verb, and powers the everyday polite request -아/어 주세요.
- -아/어 있다: Resultant StateTOPIK 2 — The resultant-state aspect: an intransitive change-of-state verb + -아/어 있다 describes the lasting state a completed change leaves behind — 앉아 있다 'be seated', 문이 열려 있다 'the door is open'.