Lesson 137: ~아/어야: One must do an action in order to do another

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단지 = building complex
시집 = one’s husband’s family/home
탈모 = hair loss
대기 = atmosphere
농도 = the concentration of something
날것 = something raw (uncooked)
지폐 = bill (of currency)
신맛 = sour taste
매장 = shop, store
화살 = arrow (that is shot)
화살표 = arrow (that points in a direction)
장학사 = superintendent
모국어 = one’s mother tongue
근육통 = muscle pain
세무서 = tax office
경비실 = security office/room

소비하다 = to consume
이수하다 = to finish a course
환기하다 = to ventilate, to air out
납부하다 = to make a payment
준수하다 = to obey/follow the rules
추락하다 = to fall
배출하다 = to discharge, to emit
호출하다 = to summon, to call
해석하다 = to interpret

Adverbs and Other Words:
손수 = with one’s own hands




In this lesson, you will learn how to add ~아/어야 to the end of a clause. You saw this grammatical principle in a previous lesson, but only followed by 하다. We will look at how this is used in all other situations. Let’s get started.



~아/어야: One must do an action in order to do another

In Lesson 46, you learned that you can attach ~아/어야 하다 to the end of a clause to indicate that one “must” do an action. For example:

세무서에 가려면 노란색 화살표를 따라가야 해요
= If you want to go to the tax office, you must follow the yellow arrows

식당을 운영하면 모든 음식의 원산지를 표시해야 해요
= If one manages a restaurant, you must display the origin of all of the food

This is actually true in Korea. Here is a video that explains one of these signs.

~아/어야 하다 is actually not an addition. The addition is simply ~아/어야. The use of 하다 at the end simply indicates that one must do the action attached to ~아/어야. I introduce it in Lesson 46 as a grammatical principle because 하다 is the most common verb that follows ~아/어야. However, in theory, any verb or adjective can be placed after ~아/어야. For example:

김치는 손수 만들어야 맛있어요
학생들이 이 수업을 이수해야 졸업할 수 있어요

I deliberately didn’t translate those two sentences. I want you to think about what an appropriate translation would be. In order for the stuff before ~아/어야 to occur, the stuff after it must happen. You could say that the following would be appropriate:

김치는 손수 만들어야 맛있어요
= Kimchi must be made at home/with one’s own hands for it to be delicious

학생들이 이 수업을 이수해야 졸업할 수 있어요
= Students must finish this course so they can graduate

Those translations are possible, but the common translation for ~아/어야 in English is “only if…” The effect is the same, though. For example:

김치는 손수 만들어야 맛있어요
= Only if kimchi is made at home/with one’s own hands is it delicious

학생들이 이 수업을 이수해야 졸업할 수 있어요
= Only if students finish this course can they graduate

Below are some more examples:

생선이 날것이어야 맛있어요
= Only if fish is raw is it delicious

지폐를 거꾸로 넣어야 들어가요
= Only if you put the bill in upside down does it go in

장학사가 학교에 오셔야 알 수 있어요
= Only if the superintendent comes to the school can we know

소득세를 세무서에서 납부해야 정확해요
= Only if you pay your tax at the tax office will it be accurate

사람들이 운전을 할 때 신호를 준수해야 안전해요
= When people drive, only when they obey the traffic signals is it safe

The example sentences used thus far have been fairly simple. Essentially, you have only seen one word after ~아/어야 – replacing 하다 from the format you are accustomed to from Lesson 46. What comes after ~아/어야 can be 하다, a verb, an adjective, or another clause altogether. For example:

창문을 열어야 방에 환기가 잘 돼요
= Only if you open the window will the room be well ventilated

Below are many more sentences:

나이키 매장에 가야 그 시발을 살 수 있어요
= Only if you go to the Nike store can you purchase those shoes

음식에 레몬을 넣어야 신맛이 나요
= Only if you put lemon in food does the sour taste come out (does it taste sour)

이 약을 발라야 근육통이 없어져요
= Only if you apply this medicine does the muscle pain go away

이 벨을 눌러서 호출해야 직원이 와요
= Only if you press this button and call a worker will one come

소금을 정확히 백 그램을 넣어야 농도가 맞아요
= Only if you put exactly one hundred grams of salt in will the concentration be correct

의사랑 일찍 상담해야 탈모를 예방할 수 있어요
= Only if you consult with a doctor early can you prevent hair loss

우리 부모님은 시집을 가야 애기를 낳을 수 있대요
= My parents say that only if I get married can I have a baby

시집을 가다 is a way to indicate that a woman gets married. Other similar words are 시아버지 and 시어머니 to refer to the father- and mother-in-law for a woman. I don’t particularly like these words, as they assume that a woman must move in to the house of her husband with his family. Whether I like these words and the term “시집을 가다” or not, Korean people use them.

가파른 절벽에 안내판이 있어야 추락을 방지할 수 있어요
= Only if there is a sign at steep cliffs can you prevent falling

사람들이 전기제품을 아껴 써야 전기소비를 줄일 수 있어요
= Only if people limit the amount that they use electronic products can we decrease the consumption of electricity

공장을 엄격하게 통제해야 오염물질을 대기에 배출하지 않을 거예요
= Only if we strictly control factories will they not discharge/belch pollutants into the atmosphere

문학 수업을 모국어로 배워야 책의 뉘앙스를 더 잘 이해할 수 있어요
= Only if you take a literature class in your own mother tongue will you be able to understand the nuances of the book(s)

아파트 단지에 들어가기 전에 경비실에 들렀다 가야 들어갈 수 있어요
= Only if you stop in to the guard room before entering the apartment complex will you be able to enter

다른 사람이 우리를 위해 말을 해석해야 우리는 서로를 이해할 수 있어요
= Only if another person interprets what we say can we understand each other


Whenever I learned a grammatical principle, I tried to force a concept into as many situations as possible. This allowed me to see what works and what doesn’t work.

I noticed that sentences with ~아/어야 usually have a positive outcome after ~아/어야. For example, notice how these two sentences end with an outcome that is positive for the speaker:

Only if we work hard will we win
Only if we add salt will it be delicious

This usually appears to be true with ~아/어야. It’s better to use it when the outcome of the sentence is positive. To further explain my point, look at this sentence:

사람들은 물을 마셔야 살아요 = Only if people drink water will they live

Living is typically advantageous to people.

You could theoretically create a similar meaning by using the opposite of “drinking” and “living.” For example:

사람들은 물을 안 마셔야 죽어요

Dying is typically disadvantageous to people. Therefore, this sentence would not be said in Korean. Instead, what you would want to say is something like this:

사람들이 물을 안 마시면 죽어요 = If people don’t drink water, they die

This doesn’t mean that the grammar within the sentence can’t be negative – but rather the outcome of the sentence usually is not negative. For example, the following sentence (also shown above) ends in 않을 거예요. It is grammatically negative, but the outcome is something positive – not discharging pollution.

공장을 엄격하게 통제해야 오염물질을 배출하지 않을 거예요


I talk about the use of 그렇다 in a lot of lessons. It’s a common word that is easily adaptable to most grammatical principles. I first talked about 그렇다 in Lesson 23.

~아/어야 is commonly added to 그렇다. For example:

그래야 맛있어요 = Only if you do it like that will it be delicious
그래야 집중을 잘 할 수 있어요 = Only if you do it like that can you concentrate well

That’s it for this lesson!