였어요)¶

If you have mastered the present tense rules in Unit 14, learning the past tense is going to be a breeze! The rules are exactly the same, you just use different endings.

1. The Past Tense Endings¶

To conjugate a verb into the past tense, you look at the last vowel of the verb stem, just like before.

There are 3 past tense endings: 았어요, 었어요, or 였어요.

Rule 1: + 았어요 (a-sseo-yo)¶

If the last vowel of the verb stem is ㅏ (a) or ㅗ (o), you add 았어요.

가다 (to go). Vowel is ㅏ. 가 + 았어요 -> 갔어요 (ga-sseo-yo). = I went.
보다 (to see). Vowel is ㅗ. 보 + 았어요 -> 봤어요 (bwa-sseo-yo). = I saw.

Rule 2: + 었어요 (eo-sseo-yo)¶

If the last vowel of the verb stem is ANYTHING ELSE (not ㅏ or ㅗ), you add 었어요.

먹다 (to eat). Vowel is ㅓ. 먹 + 었어요 -> 먹었어요 (meo-geo-sseo-yo). = I ate.
마시다 (to drink). Vowel is ㅣ. 마시 + 었어요 -> 마셨어요 (ma-syeo-sseo-yo). = I drank.

Rule 3: 하다 -> 했어요 (hae-sseo-yo)¶

Just like in the present tense, the verb 하다 (to do) is an exception. In the past tense, it changes to 했어요 (hae-sseo-yo).

하다 (to do) -> 했어요 (I did)
공부하다 (to study) -> 공부했어요 (I studied)
일하다 (to work) -> 일했어요 (I worked)

2. Comparing Present vs Past¶

Look at how similar the present and past forms are:

Dictionary	Present	Past
가다 (go)	가요	갔어요 (went)
먹다 (eat)	먹어요	먹었어요 (ate)
하다 (do)	해요	했어요 (did)

You will notice that the past tense always contains the double consonant ㅆ at the bottom of the block! This is a huge clue that a sentence is in the past tense.

Summary¶

Vowel is ㅏ or ㅗ -> add 았어요.
Vowel is anything else -> add 었어요.
하다 -> 했어요.