고

Used to connect two clauses or to list adjectives and verbs.

You are going to see 고 in a lot of grammar points, it is used a lot to make connections.

Conjugation

Polite

친구를 만나고 집에 갈 거예요.
I'm going to meet my friend and go home.

Polite

손을 씻고 저녁 식사를 하세요.
Wash your hands and eat dinner.

Polite

이 분은 엄마이고 저 분은 아빠예요.
This is my mother and this is my father.

Casual

오늘은 날씨가 나쁘고 추워.
The weather today is bad and cold.