Past Tense · -았어요/었어요

4. Common mistakes

❌ Mistake 1 — -았어요 after the wrong vowel

✖ 점심을 먹았어요.
✔ 점심을 먹었어요.
  jeom-si-meul meo-geo-sseo-yo.

The last vowel of 먹 is ㅓ, not ㅏ or ㅗ, so the ending is -었어요. Check the vowel in the last syllable of the stem each time. It is easy to type -았어요 by habit.

❌ Mistake 2 — 하었어요

✖ 어제 숙제를 하었어요.
✔ 어제 숙제를 했어요.
  eo-je suk-je-reul hae-sseo-yo.

하다 is a special case. It always becomes 했어요, and the same holds for 공부하다, 일하다 and every other 하다 verb. Never add 었 to 하.

❌ Mistake 3 — 였어요 after a consonant

✖ 저는 학생였어요.
✔ 저는 학생이었어요.
  jeo-neun hak-saeng-i-eo-sseo-yo.

학생 ends in a consonant, so you need 이었어요. Use 였어요 only after a vowel, as in 의사였어요 and 가수였어요. The 이 is a real part of the word, so it cannot disappear after a consonant.

❌ Mistake 4 — Not joining the vowels

✖ 어제 학교에 가았어요.
✔ 어제 학교에 갔어요.
  eo-je hak-gyo-e ga-sseo-yo.

When the stem is 가, the vowel ㅏ and 았 must merge into one syllable, so you get 갔어요. The same happens with 샀, 잤 and 만났, and 오 + 았 contracts to 왔. The long form 마시었어요 is a rare exception that is still grammatical, but 마셨어요 is what you will hear.

❌ Mistake 5 — Present tense with a past time word

✖ 어제 영화를 봐요.
✔ 어제 영화를 봤어요.
  eo-je yeong-hwa-reul bwa-sseo-yo.

The word 어제 tells us the action is finished, so the verb must be in the past. 봐요 is present, so it sounds wrong with yesterday. Match the verb to the time word, and the same goes for 지난주 and 아까.