Today, we are learning the most important grammar pattern for expressing obligation and necessity in Korean: -아야/어야 하다.
This is the most common way to say "I must," "I have to," or "I should" do something. You'll use this pattern every day to talk about your responsibilities, plans, and even to give strong advice.
1. Usage: Understanding -아야/어야 하다
This grammar pattern is attached to verbs and adjectives to show that an action or state is necessary or required.
Function 1: Obligation / Necessity ("must" / "have to")
This is the primary use. It states that an action is a duty or a requirement.
- Korean: 학교에 가야 해요.
English: "I have to go to school." - Korean: 숙제를 해야 해요.
English: "I must do my homework."
Function 2: Strong Advice / Recommendation ("should")
You can also use it to give strong advice or to say that something is a good idea (i.e., "you really should...").
- Korean: 이 책을 읽어야 해요. 정말 재미있어요.
English: "You should read this book. It's really fun." - Korean: 약을 먹어야 해요.
English: "You must take your medicine."
2. Conjugation: How to Form -아야/어야 하다
The conjugation is based on the same rules as -아요/어요. You take the verb stem, add the appropriate connective, and then add -야 하다.
Rule 1: Last vowel is ㅏ or ㅗ
If the last vowel of the stem is ㅏ or ㅗ, you add -아야 하다.
- 가다 (to go) → 가 + -야 하다 = 가야 하다
- 보다 (to see) → 보 + -아야 하다 = 봐야 하다 (Contraction)
- 좋다 (to be good) → 좋 + -아야 하다 = 좋아야 하다
Rule 2: Last vowel is NOT ㅏ or ㅗ
If the last vowel is anything else (ㅓ, ㅜ, ㅣ, ㅡ, etc.), you add -어야 하다.
- 먹다 (to eat) → 먹 + -어야 하다 = 먹어야 하다
- 읽다 (to read) → 읽 + -어야 하다 = 읽어야 하다
- 마시다 (to drink) → 마시 + -어야 하다 = 마셔야 하다 (Contraction)
- 예쁘다 (to be pretty) → 예뻐야 하다 (Contraction)
Rule 3: 하다 Verbs
All verbs ending in 하다 become -해야 하다 (a contraction of 하여야 하다).
- 공부하다 (to study) → 공부해야 하다
- 일하다 (to work) → 일해야 하다
Conjugating for Tense (Present, Past, Future)
This is very important! The -야 하- part stays the same. You conjugate the final 하다 part for tense.
- Present: -아야/어야 해요 (I have to...)
- Past: -아야/어야 했어요 (I had to...)
- Future: -아야/어야 할 거예요 (I will have to...)
3. Example Sentences
Let's see how this works in different situations.
- Korean: 지금 집에 가야 해요.
English: I have to go home now. (Present) - Korean: 어제 일을 해야 했어요.
English: I had to work yesterday. (Past) - Korean: 내일 일찍 일어나야 할 거예요.
English: I will have to wake up early tomorrow. (Future) - Korean: 뭘 해야 해요?
English: What should I do? (Question) - Korean: 한국어를 열심히 공부해야 해요.
English: I must study Korean hard. - Korean: 우리는 약속을 지켜야 해요.
English: We must keep our promises. (From 지키다) - Korean: 도서관에서는 조용히 해야 해요.
English: You must be quiet in the library. - Korean: 이 약을 밥 먹고 30분 후에 먹어야 해요.
English: You have to take this medicine 30 minutes after eating a meal.
4. Key Rules and Comparisons
Here are a few crucial points to remember.
Rule 1: The Common Sibling: -아야/어야 되다
You will hear -아야/어야 되다 just as often as -아야/어야 하다. For beginners, they are mostly interchangeable.
- ...야 하다: Implies obligation, often from one's own will or a general rule. (I must do this.)
- ...야 되다: Implies obligation from an external situation, rule, or permission. (It has to be done / I'm supposed to do this.)
In daily conversation, don't worry too much. Both 해야 해요 and 해야 돼요 are used to mean "I have to do it."
Rule 2: The Strong Negative: "Must Not" (-(으)면 안 되다)
This is NOT the opposite of "have to." This is a strong prohibition: "You must not..."
Rule 3: The True Opposite: "Don't Have to" (-지 않아도 되다)
If you want to say "You don't have to..." (it's not necessary), you must use a different pattern: -지 않아도 되다.
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