Korean past tense

In Korean, the past tense is used to describe actions that have already happened. The past tense can be formed in several ways, depending on the verb type and formality level. Here's an overview of how to form the past tense in Korean:

**Regular Verbs:**

For regular verbs, the past tense is formed by adding the suffix "-았/었-" to the verb stem. The choice between "-았-" and "-었-" depends on the final vowel of the verb stem.

- If the verb stem ends in a vowel, use "-았-": 

  - Example: 먹다 (to eat) → 먹었어요 (ate)

- If the verb stem ends in a consonant, use "-었-": 

  - Example: 가다 (to go) → 갔어요 (went)

**Irregular Verbs:**

Irregular verbs in Korean have unique conjugation patterns for the past tense. Some common irregular verbs include 가다 (to go), 오다 (to come), and 하다 (to do).

- 가다 (to go): 갔어요 (went)

- 오다 (to come): 왔어요 (came)

- 하다 (to do): 했어요 (did)

**Formality Levels:**

Korean has different levels of formality, and the past tense can be conjugated accordingly:

- **Polite Form (요 form):** Add the polite ending "-요" after the past tense marker.

  - Example: 먹었어요 (ate) + 요 = 먹었어요 (ate, polite)

- **Casual Form (아/어 form):** Remove the polite ending "-요" and use the appropriate verb ending.

  - Example: 먹었어요 (ate) → 먹었어 (ate, casual)

**Negative Past Tense:**

To form the negative past tense, use the negative marker "-았/었-" or "-지 않았/었-". For example:

- 먹다 (to eat) → 먹지 않았어요 (didn't eat)

- 가다 (to go) → 가지 않았어요 (didn't go)

**Summary:**

- Regular verbs: Add "-았/었-" to the verb stem.

- Irregular verbs: Follow their specific conjugation patterns.

- Formality levels: Use the appropriate ending for the desired level of formality.

- Negative past tense: Use the negative marker "-지 않았/었-".