Lesson 37 · Things You Need to Do: -아/어야 해요/돼요
Hyeju’s Beginner Korean · Lesson 37 · Grammar
Things You Need to Do: -아/어야 해요/돼요
Learn Things You Need to Do: -아/어야 해요/돼요 with form rules, natural examples, common mistakes, romanization, and six practice questions with answers.
Introduction / Review
Use -아/어야 해요 or -아/어야 돼요 for a necessary action: “have to” or “need to.” Compare permission, 먹어도 돼요, with obligation, 먹어야 돼요.
N = noun; V = action verb; A = descriptive verb. Romanization is a reading aid.
Today’s Grammar / Explanation
- 아/어 form + 야 해요/돼요: 가다 → 가야 해요; 먹다 → 먹어야 해요; 하다 → 해야 해요.
- Irregulars: 듣다 → 들어야 해요; 걷다 → 걸어야 해요; 쓰다 → 써야 해요.
- Past obligation changes the final predicate: 가야 했어요 (“I had to go”). Today’s core practice uses present 해요/돼요.
Examples
오늘 숙제를 해야 해요.
oneul sukjereul haeya haeyo
I have to do my homework today.
내일 일찍 일어나야 해요.
naeil iljjik ireonaya haeyo
I need to get up early tomorrow.
손을 씻어야 해요.
soneul ssiseoya haeyo
I need to wash my hands.
병원에 가야 해요.
byeongwone gaya haeyo
I need to go to the hospital.
여기에 이름을 써야 해요.
yeogie ireumeul sseoya haeyo
You need to write your name here.
오늘 해야 돼요.
oneul haeya dwaeyo
It has to be done today.
Compare with similar grammar
LESSON 36
-아/어도 돼요
지금 집에 가도 돼요.Permission, “may”. -아/어야 해요 is the opposite direction: obligation.
Review Lesson 36 →LESSON 85
-(으)ㄹ 수밖에 없어요
버스가 끊겼어요. 택시를 탈 수밖에 없어요.Stronger: “there’s no choice but to”, usually because of the situation.
Look ahead: Lesson 85 →LESSON 34
-(으)세요
이 약을 하루에 세 번 드세요.-(으)세요 gives the listener an instruction or advice. -아/어야 해요 states what is necessary.
Review Lesson 34 →LESSON 33
-(으)려고 해요
내일은 일찍 일어나려고 해요.Something you choose to do. -아/어야 해요 is something you need to do.
Review Lesson 33 →| Pattern | Meaning | Example |
|---|---|---|
| -아/어야 해요 | have to, must | 가야 해요 |
| -아/어야 돼요 | have to (very common in speech) | 가야 돼요 |
| 안 -아/어도 돼요 | don’t have to | 안 가도 돼요 |
| -(으)면 안 돼요 | must not | 가면 안 돼요 |
Dialogue: The Night Before a Trip
Minsu is flying out early tomorrow, and Yuna helps him check what he has to do. Listen for -아/어야 해요/돼요 and for the opposite, 안 -아/어도 돼요.
Point: 싸야 해요 and 가져가야 돼요 mean the same thing. 일어나야 할 거예요 adds a guess about the future. To say something is not necessary, use 안 해도 돼요, not 안 해야 해요.
Must, May, Don’t Have To, Must Not
These four patterns are easy to mix up. Keep them together in your notes.
| Pattern | Meaning | Example |
|---|---|---|
| -아/어야 해요/돼요 | must, have to | 여권을 가져가야 해요. |
| -아/어도 돼요 | may, it’s okay to | 여기 앉아도 돼요. |
| 안 -아/어도 돼요 | don’t have to | 예약 안 해도 돼요. |
| -(으)면 안 돼요 | must not | 여기에서 사진을 찍으면 안 돼요. |
Common mistakes
To say an action is unnecessary, use 안 …-아/어도 돼요 from Lesson 36. 안 가야 해요 means that not going is necessary; it does not mean “You don’t have to go.”
The pattern ends in 해요 or 돼요, not 있어요.
하다 → 해야.
야 attaches to the -아/어 form: 먹어야.
“Don’t have to” is 안 -아/어도 돼요. 안 가야 해요 means “must not go”.
Mini practice · six questions
All sentences below are new. Try each one before opening the answer.
- Fill in the blank비자가 필요해요. 내일 대사관에 ______. (가다)
Check answer
내일 대사관에 가야 해요.
가 + 아야 해요 → 가야 해요.
- Fill in the blank내일 시험이 있어요. 오늘 밤에 ______. (공부하다)
Check answer
오늘 밤에 공부해야 해요.
하다 → 해야 해요.
- Choose the correct form내일은 휴일이에요. 회사에 (안 가도 돼요 / 가야 돼요).
Check answer
안 가도 돼요
It’s a holiday, so you don’t have to go.
- Choose the correct form감기에 걸렸어요. 약을 (먹어야 해요 / 먹어도 돼요).
Check answer
먹어야 해요
You’re sick, so taking medicine is necessary.
- Find and fix the mistake우리는 다섯 시까지 공항에 도착하야 해요.
Check answer
우리는 다섯 시까지 공항에 도착해야 해요.
도착하다 → 도착해야.
- Say it in KoreanI have to buy a birthday present for my mom.
Check answer
엄마 생일 선물을 사야 해요.
사 + 아야 해요 → 사야 해요.
Questions Learners Often Ask
해야 해요 or 해야 돼요?
They mean the same thing, and both are correct. In everyday speech, 해야 돼요 is very common; 해야 해요 sounds a little more neutral and is common in writing.
How do I say “I had to …”?
Change only the last verb: 가야 했어요 or 가야 됐어요 (“I had to go”). The 아/어야 part stays the same.
How do I say “You must not …”?
Do not use 안 -아/어야 해요. Use -(으)면 안 돼요: 늦으면 안 돼요 (“You must not be late”).
Today’s Key Point
아/어야 해요/돼요 = necessity; 도 grants permission, 야 expresses obligation; 하다 becomes 해야.
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