Honorific -(으)시-

When the subject of a sentence is someone you respect (a teacher, your boss, a grandparent, a customer), Korean adds -(으)시- to the verb. In polite speech this gives -(으)세요, in formal speech -(으)십니다, and formal questions end in -(으)십니까. You already know -(으)세요 from polite requests; here it simply describes what the respected person does. It is also used when the subject is something of theirs: 부장님은 키가 크세요 (The manager is tall).

• Vowel stem: 가다 → 가세요, 하다 → 하세요
• Consonant stem, add 으: 읽다 → 읽으세요, 받다 → 받으세요
• ㄹ stem, the ㄹ drops and no 으 is added: 살다 → 사세요, 만들다 → 만드세요
• Irregular stems: 듣다 → 들으세요, 걷다 → 걸으세요, 돕다 → 도우세요, 춥다 → 추우세요

Never use -시- about yourself: 저는 학교에 가요 (I go to school).