Korean Past Tense: Understanding 았/었 Grammar

Korean past tense is formed by adding specific endings to verb stems. The two main past tense endings are 았 and 었, and choosing between them depends on the vowel harmony rules of the Korean language. This guide will help you understand when and how to use each ending correctly.

Basic Grammar Rules

1. When to Use 았 (at)

Use 았 when the verb stem contains:

• Bright vowels: ㅏ (a), ㅗ (o)
• The verb 하다 (hada – to do)

2. When to Use 었 (eot)

Use 었 when the verb stem contains:

• Dark/neutral vowels: ㅓ (eo), ㅜ (u), ㅡ (eu), ㅣ (i), ㅑ (ya), ㅕ (yeo), ㅛ (yo), ㅠ (yu), etc.

3. Contraction Rules

Important contractions to remember:

• 하 + 았 → 했 (haet)
• ㅏ + 았 → ㅏ았 → ㅏㅆ (double consonant)
• ㅗ + 았 → ㅘㅆ
• ㅓ + 었 → ㅓㅆ
• ㅜ + 었 → ㅝㅆ

Conjugation Patter

Informal Past Tense (Casual)

• Verb stem + 았어/었어

Formal Past Tense (Polite)

• Verb stem + 았습니다/었습니다

Past Tense with 았/었

Example Sentences

Using 았 (ㅏ, ㅗ )

가다 (gada) – to go

• 어제 학교에 갔어요. – Yesterday I went to school.
• 친구가 집에 갔습니다. – My friend went home.

오다 (oda) – to come

• 언니가 늦게 왔어요. – My sister came late.
• 손님이 일찍 왔습니다. – The guest came early.

자다 (jada) – to sleep

• 어젯밤에 일찍 잤어요. – I slept early last night.
• 아기가 조용히 잤습니다. – The baby slept quietly.

만나다 (mannada) – to meet

• 친구를 카페에서 만났어요. – I met my friend at the cafe.
• 선생님을 복도에서 만났습니다. – I met the teacher in the hallway.

Using 었 (Vowels other than ㅏ and ㅓ)

먹다 (meokda) – to eat

• 점심을 맛있게 먹었어요. – I ate lunch deliciously.
• 어머니가 저녁을 준비해서 먹었습니다. – Mother prepared dinner and we ate it.

보다 (boda) – to see/watch

• 영화를 재미있게 봤어요. – I watched the movie enjoyably.
• 뉴스를 집중해서 봤습니다. – I watched the news with concentration.

읽다 (ikda) – to read

• 책을 다 읽었어요. – I finished reading the book.
• 신문을 아침에 읽었습니다. – I read the newspaper in the morning.

듣다 (deutda) – to listen/hear

• 음악을 크게 들었어요. – I listened to music loudly.
• 라디오를 차에서 들었습니다. – I listened to the radio in the car.

Using 했 (하다 Verbs)

공부하다 (gongbuhada) – to study

• 한국어를 열심히 공부했어요. – I studied Korean diligently.
• 시험을 위해 밤늦게 공부했습니다. – I studied late at night for the exam.

요리하다 (yorihada) – to cook

• 어머니가 맛있는 음식을 요리했어요. – Mother cooked delicious food.
• 친구와 함께 파스타를 요리했습니다. – I cooked pasta together with my friend.

운동하다 (undonghada) – to exercise

• 아침에 공원에서 운동했어요. – I exercised in the park in the morning.
• 헬스장에서 한 시간 동안 운동했습니다. – I exercised for one hour at the gym.

Vocabulary Reference

Common Verbs with 았

Common Verbs with 었

Common 하다 Verbs

Grammar Points to Remember

1. Vowel Harmony

Korean follows vowel harmony rules. Bright vowels (ㅏ, ㅗ) pair with 았, while dark/neutral vowels pair with 었.

2. Irregular Verbs

Some verbs have irregular conjugations:

• 듣다 (deutda) → 들었다 (deureotda) – “to listen”
• 짓다 (jitda) → 지었다 (jieotda) – “to build”
• 눕다 (nupda) → 누웠다 (nuwotda) – “to lie down”

3. Contraction Rules

Pay attention to contractions that make pronunciation smoother:

• 보다 → 봤다 (not 보았다)
• 하다 → 했다 (not 하았다)

4. Formality Levels

Remember to match the formality level:

• Casual: 갔어, 먹었어, 했어
• Polite: 갔어요, 먹었어요, 했어요
• Formal: 갔습니다, 먹었습니다, 했습니다

Practice Tips

1. Listen to the stem vowel: The last vowel in the verb stem determines which ending to use.
2. Practice contractions: Common contractions like 했다, 봤다, 갔다 should become automatic.
3. Use time expressions: Combine past tense with time words like 어제 (yesterday), 지난주 (last week), 작년 (last year).
4. Start with regular verbs: Master regular conjugations before moving to irregular verbs.

Understanding 았/었 past tense endings is fundamental to expressing past actions in Korean. With consistent practice and attention to vowel harmony rules, you’ll be able to use these endings naturally in conversation.