Past Tense: 았/었어요
Turn present tense sentences into past tense using 았/었어요.
Past tense in Korean is formed by inserting -았/었- between the verb stem and the polite ending -어요. The vowel choice follows the same harmony rule as the present: ㅏ/ㅗ stems take -았어요, everything else takes -었어요. 하다 verbs become 했어요.
Examples: 먹다 (eat) → 먹었어요 (ate), 가다 (go) → 갔어요 (went — the ㅏ of 가 fuses with the 았 of -았어요 to produce 갔), 마시다 (drink) → 마셨어요 (drank), 공부하다 (study) → 공부했어요 (studied). The past tense in Korean is just one tense — there is no distinction between 'I ate' / 'I have eaten' / 'I was eating' the way English makes. Context tells you which English equivalent fits. This makes Korean past tense easier than English past tense for once.
Past Tense: 았/었어요
Same vowel rule as present: if stem vowel is ㅏ/ㅗ → 았어요, otherwise → 었어요, 하다 → 했어요. Just replace 아요/어요 with 았어요/었어요.
Time Words for Past Tense
Common time words: 어제 (yesterday), 지난주 (last week), 지난달 (last month), 작년 (last year), 아까 (a while ago), 방금 (just now).
How It Works
The past tense is built on the present, which makes it unusually cheap to learn. Take the 아/어 form you already know and insert ㅆ before the ending: 아요 becomes 았어요, 어요 becomes 었어요, 해요 becomes 했어요. The vowel-harmony decision has already been made when you formed the present, so there is no new rule to apply.
가요 becomes 갔어요, 먹어요 becomes 먹었어요, 공부해요 becomes 공부했어요. Contractions carry over unchanged too: 와요 becomes 왔어요, 줘요 becomes 줬어요, 마셔요 becomes 마셨어요. If you can conjugate the present, you can conjugate the past by pattern-matching rather than by rule.
The ㅆ here is the tense consonant from Level 1-5, which is why every past-tense verb in Korean contains one. This is the grammatical reason that lesson insisted you cannot avoid ㅆ.
One difference from English is worth flagging. Korean past tense also covers states that began in the past and still hold. 결혼했어요 means 'I got married' but is the normal way to say 'I am married'. Similarly 배가 고팠어요 describes hunger that started earlier. Reading every past form as strictly completed-and-finished will occasionally mislead you.
Where You'll Hear It
Past tense unlocks the most common category of small talk in Korean. 밥 먹었어요? ('have you eaten?') functions as a genuine greeting, closer to 'how are you' than to a real question about food, and answering it correctly is a small social milestone.
The time words in this lesson combine with past forms constantly. 어제 친구를 만났어요, 지난주에 영화를 봤어요, 아까 점심을 먹었어요. Note that 어제 takes no particle while 지난주 takes 에 — a quirk worth absorbing early rather than fighting.
Because Korean drops pronouns freely, the past tense often carries the whole weight of a reply. Asked 뭐 했어요?, you can answer simply 공부했어요 with no subject at all, and it is completely natural.
The state-versus-event issue shows up immediately in introductions. If someone asks whether you are married, the answer uses 했어요, and hearing it as 'I did marry, once' rather than 'I am married' produces exactly the kind of confusion that makes learners think they have misunderstood.
Cultural & Language Note
Korean past tense is marked once, on the verb at the end of the sentence, and time words like 어제 do not need to agree with it. This is the same economy Japanese has. English, by contrast, forces agreement across the clause. The practical upshot is that once you attach 았/었, the rest of the sentence needs no adjustment.
Common Mistakes to Avoid
The vowel rule from the present tense carries over: stems with ㅏ or ㅗ take 았어요, everything else takes 었어요, and 하다 becomes 했어요. Learners often default to 었어요 for everything. Another frequent slip is doubling the past marker in compound expressions — once is enough, on the final verb.
How to Practice This Lesson
Do not learn the past tense as a new conjugation. Learn it as a transformation you apply to forms you already have. Write a column of present-tense verbs you know and convert each one; the mechanical repetition is what builds speed.
Pay particular attention to the contracted verbs, because those are the ones that feel unfamiliar in past form. 왔어요, 봤어요, 줬어요, 마셨어요 should be drilled as units until they sound ordinary.
Then tell your actual yesterday out loud — five or six sentences, each with a time word. Personal narrative is the natural home of the past tense, and describing your own day forces you to reach for verbs you genuinely use rather than the ones a textbook happens to list. Repeat the same account on several consecutive days and you will notice the forms arriving faster each time.