Core Grammar Rule: Past Tense Marker -았/었-
In Korean, you change the verb or adjective ending to show that an action or state occurred in the past. The past tense marker -았/었- is attached directly to the stem of the verb or adjective.
Meaning & Usage
Meaning: It's equivalent to the simple past tense in English (e.g., "ate," "was," "studied"). It indicates a completed action or a state that was true in the past.
When to use: Use it whenever you're talking about something that has already happened, whether it was yesterday, last week, or ten years ago. It's fundamental for telling stories, sharing experiences, or explaining past events.
Conjugation Rules
Rule: The choice between -았- and -었- depends on the last vowel of the verb/adjective stem. If the stem is a 하다 verb, it becomes -했-.
Last vowel is ㅏ or ㅗ: Attach -았어요 (polite) or -았어 (casual). Example: 가다 (to go) → 가 + 았어요 → 갔어요 (went). 보다 (to see) → 보 + 았어요 → 봤어요 (saw).
Last vowel is NOT ㅏ or ㅗ: Attach -었어요 (polite) or -었어 (casual). Example: 먹다 (to eat) → 먹 + 었어요 → 먹었어요 (ate). 읽다 (to read) → 읽 + 었어요 → 읽었어요 (read).
하다 verbs: These verbs always change to -했어요 (polite) or -했어 (casual). Example: 공부하다 (to study) → 공부했어요 (studied). 일하다 (to work) → 일했어요 (worked).
Vowel ㅏ/ㅗ: + -았- / Other Vowels: + -었- / 하다 Verbs: -했-
Time Particle ~에
The particle ~에 is essential for specifying when something happens. It attaches to nouns related to time, like days of the week, dates, and specific times of day.
Usage with Days and Dates
Context: When you want to pinpoint an event on a specific day or date, you attach ~에 directly to the noun. This is similar to using "on" in English (e.g., on Monday, on the 5th).
Example: 저는 토요일에 영화를 봤어요. (I watched a movie on Saturday.) / 10월 9일에 한글날이에요. (It's Hangeul Day on October 9th.)
When NOT to Use ~에
Context: While ~에 is used for specific points in time, it is generally NOT used with relative time words like 어제 (yesterday), 오늘 (today), 내일 (tomorrow), or 언제 (when). These words function as adverbs on their own and don't require a particle.
Example: 어제 친구를 만났어요. (I met a friend yesterday.) — Not 어제에. / 내일 뭐 할 거예요? (What are you going to do tomorrow?) — Not 내일에.
[Day/Date] + 에: 토요일에 (on Saturday) / [Relative Time Word]: 어제 (yesterday)
Explaining Mistakes: 착각했어요 vs. 잊었어
When you make a mistake about a plan, there are a few different ways to explain what happened. The word you choose depends on the type of mistake.
착각했어요 (I was mistaken)
Use 착각하다 when you misperceived or misunderstood a fact. It implies you had the wrong information in your head. Junwoo uses this when he realizes he already had a presentation scheduled on the day he just agreed to.
Example: 미안해요. 제가 수요일을 다음 주로 착각했어요. (I'm sorry. I mistakenly thought Wednesday was next week.)
잊었어요 / 잊었어 (I forgot)
Use 잊다 when the information completely slipped your mind. You knew it, but you forgot. Minji uses this when she realizes she forgot her friend's birthday.
Example: 진짜 미안해. 내가 완전히 잊었어. (I'm so sorry. I completely forgot.)
제가 착각했어요 / 내가 완전히 잊었어
Suggesting a Time: ~은/는 어때요?
A very common and natural way to suggest a time or day is by using the pattern [Time/Day] + 은/는 어때요? (polite) or ~어때? (casual). It literally means "How about [Time/Day]?"
Making a Suggestion
Attach ~은 to nouns ending in a consonant and ~는 to nouns ending in a vowel.
Polite: 준우 asks, "오후 3시 어때요?" (How about 3 PM?) and 수민 asks, "그럼 금요일은 어떠세요?" (Then how about Friday?)
Responding to a Suggestion
A simple and positive way to agree is with 좋아요 (Good / I like it) or 괜찮아요 (It's fine / It's okay).
Examples from the dialogue: "수요일 좋아요." (Wednesday is good.) and "금요일은 괜찮아요." (Friday is fine.)
오후 3시 어때요? / 금요일은 어떠세요?
Politeness & Formality
Asking about someone's plans or past actions requires different levels of politeness depending on your relationship with them.
Asking Politely (해요체)
Context: Use this form with people you've just met, older people, colleagues, or in any formal or professional setting. It shows respect. The key is the ~요 ending.
Example: 주말에 뭐 하셨어요? (What did you do on the weekend?) / 수요일에 시간 괜찮으세요? (Are you free on Wednesday?)
Asking Casually (반말)
Context: Use this form only with close friends, younger siblings, or people you have an established casual relationship with. Using it with a stranger or someone older would be considered rude. The ~요 is dropped.
Example: 주말에 뭐 했어? (What'd you do on the weekend?) / 수요일에 시간 괜찮아? (Are you free on Wednesday?)
Polite: 주말에 뭐 하셨어요? / Casual: 주말에 뭐 했어?