Past tense detailed: 았/었/였 selection

Korean verbs change based on their last vowel. This is called vowel harmony. It is like matching your socks to your shoes. Some vowels are "bright" and like to hang out together. Some vowels are "dark" and prefer their own group. When you want to say something happened in the past, you look at the verb stem. You then choose the ending that matches that stem's vibe. Think of it like a grammar traffic light. Green means go with one ending, red means another. Once you see the pattern, you will spot it everywhere. Even native speakers had to learn this once, so take your time.

1. 1Follow these three simple steps to master the past tense:
2. 2Find the verb stem by dropping 다 from the dictionary form.
3. 3Look at the very last vowel in that stem.
4. 4If the vowel is ㅏ or ㅗ, add 았어요 (for polite speech).
5. 5If the vowel is anything else (like ㅓ, ㅜ, ㅣ), add 었어요.
6. 6If the verb ends in 하다, it always changes to 했어요.
7. 7Let's look at some quick examples. For 가다 (to go), the stem is 가. The vowel is ㅏ, so it becomes 갔어요. For 먹다 (to eat), the stem is 먹. The vowel is ㅓ, so it becomes 먹었어요. For 공부하다 (to study), it simply becomes 공부했어요. It is like a puzzle where the pieces finally click together.

Use this pattern whenever an action is completely finished. Use it when you are ordering food and want to say you already paid. Use it during a job interview to describe your past experiences. It is perfect for asking directions if you want to say "I already walked three blocks." You will use it when texting friends about the movie you watched last night. It is the bread and butter of daily communication. If the action is over, this is your go-to grammar. It makes your Korean sound natural and clear.

Do not use this for things you are doing right now. If you are currently eating, use the present tense instead. Also, avoid using it for future plans or promises. Korean has a different set of endings for the future. If you say 갔어요 when you mean "I will go," people will be very confused. They might think you have a secret time machine! Also, be careful with adjectives that describe a current state. If you are hungry right now, don't use the past tense. Only use it if you were hungry ten minutes ago but just ate a snack.

Many people forget to contract the vowels. For example, 보다 (to see) becomes 보았어요, which usually shrinks to 봤어요. Writing 보았어요 isn't wrong, but it sounds a bit like a textbook talking. Another mistake is using 았 for every single verb. Remember the vowel harmony rule! 먹았어요 is a very common error for beginners. It should always be 먹었어요 because ㅓ is a dark vowel. Yes, even native speakers mess this up when they are typing fast! Just take a breath and check your vowels.

In English, we have "I went" and "I have gone." Korean is a bit simpler at this level. The 았/었/였 pattern covers most simple past actions. However, do not confuse it with the ~고 있었다 pattern. That one is for things you "were doing" over a period of time. Our current pattern is for the simple fact that it happened. Think of 았/었/였 as a snapshot of a finished moment. Later, you will learn 았었/었었, which is like the "past-past" tense. But for now, focus on the basic three. They will get you through 90% of your daily conversations.