Nadia is correct. I'd like to add some more details to her explanation. 'ㅂ' irregular conjugation is also found not only in adjectives but also in verbs. Here are some examples. 1. 'ㅂ'irregular verbs 돕다 (to help)--> 도 + 와요 --> 도와요 굽다 (to bake) --> 구 + 워요 --> 구워요 줍다 (to pick)--> 주 + 워요 --> 주워요 2. 'ㅂ' irregular adjectives 춥다 --> 추 + 워요 --> 추워요 덥다 --> 더 + 워요--> 더워요 차갑다 --> 차가 + 워요 --> 차가워요 3. *'ㅂ' regular verbs 잡다 (to catch) --> 잡아요 뽑다 (to pull out) --> 뽑아요 4. 'ㅂ' regular adjectives 좁다 (to be narrow) --> 좁아요

I'm learning Korean for a year, and i know that if an adjective/a verb ends in ㅂ , the "ㅂ" changes to 우 or 오. Here: ㅂ-->우 + 어요= 워요