[Grammar] -(아/어/여)야 하다/되다 have to

v+(아/어/해)야 하다/되다

means ‘should, must, have to’ in English. You can also use 하다 instead of 되다, 하다 is a little bit formal than 되다. The conjugation is

verb stem ends with 아, 오 + 아야 하다/되다 
verb stem ends with other than  아/오 + 어야 하다/되다 
verb stem ends with 하 + 여야 하다/되다 => 해야 하다/되다 

Example)

지금 집에 가야 돼요.  I have to go home now.
오늘 일을 많이 해야 돼요.  I have to do a lot of work today.
이 약을 먹어야 돼요.  I have to take this medicine.
새 핸드폰을 사야 돼요.  I have to buy a new cell phone.
물을 많이 마셔야 돼요.  You(we, I) should drink a lot of water.
이 편지를 오늘 꼭 보내야 돼요. I must send this letter by today.
집을 청소해야 돼요. I have to clean the house.
너무 피곤해요. 집에서 쉬어야 돼요. I am so tired. I have to rest at home.
한국어로 일기를 써야 돼요. (click here to study 으 drop verb) I should write diary in Korean.
많이 걸어야 돼요. (click here to study ㄷ irregular verb) You(we, I) have to walk a lot.

Then how to say ‘you should not do’? It is -(으)면 안 되다. (click here to study)

You can listen to the audio file by clicking here.