Past tense formation: -았/었/했어요 using vowel harmony
Can form past tense sentences and talk about completed actions
Look at these examples. Can you spot the grammar pattern?
어제 학교에 갔어요.
I went to school yesterday.
점심을 먹었어요.
I ate lunch.
영화를 봤어요.
I watched a movie.
주말에 뭐 했어요?
What did you do on the weekend?
Pay attention to the highlighted parts. What do they have in common?
The past tense in Korean uses -았/었/했 + 어요. The vowel harmony rules are the same as present tense — just add ㅆ (ssang-siot) to the ending.
Formation:
| Last vowel | Present | Past |
|---|---|---|
| ㅏ or ㅗ | -아요 | -았어요 |
| Other vowels | -어요 | -었어요 |
| 하다 | -해요 | -했어요 |
Examples:
| Dictionary | Present | Past |
|---|---|---|
| 가다 (go) | 가요 | 갔어요 (가+았→갔) |
| 먹다 (eat) | 먹어요 | 먹었어요 |
| 오다 (come) | 와요 | 왔어요 (오+았→왔) |
| 마시다 (drink) | 마셔요 | 마셨어요 |
| 공부하다 (study) | 공부해요 | 공부했어요 |
| 보다 (see) | 봐요 | 봤어요 (보+았→봤) |
Pattern: If you know the present tense form, the past is easy — just insert ㅆ before 어요:
Negative past: 안 + past, or stem + 지 않았어요: 안 갔어요 / 가지 않았어요 (didn't go).
Apply this grammar in A1 course exercises
Practice ExercisesApplied wrong vowel harmony in past tense (았 vs 었)
Same rule as present: ㅏ/ㅗ → 았어요, others → 었어요, 하다 → 했어요
Failed to contract past tense correctly
Past contractions: 가+았→갔, 오+았→왔, 보+았→봤, 마시+었→마셨, 하+였→했
어제 학교에 갔어요.
I went to school yesterday.
가다 → past: 가 (stem, ㅏ) + 았어요 → 갔어요 (contracted). 어제 (yesterday) confirms past context.
점심을 먹었어요.
I ate lunch.
먹다 → past: 먹 (stem, ㅓ — not ㅏ/ㅗ) + 었어요 → 먹었어요. No contraction needed since stem ends in consonant.
영화를 봤어요.
I watched a movie.
보다 → past: 보 (stem, ㅗ) + 았어요 → 봤어요 (ㅗ+ㅏ→ㅘ, plus ㅆ). Same contraction as present 봐요, just with ㅆ.
주말에 뭐 했어요?
What did you do on the weekend?
하다 → past: 했어요. The most common past tense form — hundreds of 하다 verbs all become ~했어요.
Practice in course
Apply this grammar in A1 course exercises