Used to express a condition of necessity. The first phrase indicates a necessary condition for the phrase that follow.

Mine:

1. 버튼을 눌러야 문이 열려요
   • The door opens if you press the button
2. 작은 소리로 불러야 닭이 와요
   • The chicken comes if you call in a low voice

Extras

1. 물을 마셔야 목이 안 말라요.
   • You must drink water to not be thirsty.
2. 공부를 해야 시험에 합격해요.
   • You must study to pass the exam.
3. 문을 닫아야 바람이 안 들어와요.
   • You must close the door to keep the wind out.
4. 일찍 자야 피곤하지 않아요.
   • You must sleep early to not be tired.
5. 비가 와야 농작물이 자라요.
   • It must rain for the crops to grow.
6. 열쇠가 있어야 문을 열 수 있어요.
   • You need to have the key to open the door.
7. 돈이 있어야 물건을 살 수 있어요.
   • You need to have money to buy things.