used to talk about something already known or mentioned
The cat I saw yesterday was black.
어제 내가 본 그 고양이는 검은색이었다.
used for the only or main one of its kind
The sun is very bright today.
오늘 태양은 매우 밝다.
used to specify which person or thing you mean
The book on the table is mine.
탁자 위에 있는 그 책은 내 것이다.
used to talk about something in general, not a specific one
The piano is a beautiful instrument.
피아노는 아름다운 악기이다.
used with adjectives to refer to a group of people or things
We should help the poor.
우리는 가난한 사람들을 도와야 한다.
used before a family name to refer to the whole family
The Smiths are coming to dinner.
스미스 가족이 저녁 식사에 온다.
used with units to mean 'every'
She gets paid by the hour.
그녀는 시간당으로 임금을 받는다.
enough of something for a purpose
I don't have the time to help you.
너를 도울 시간이 없다.
used with time to mean 'the present'
This is the song of the day.
이것은 오늘의 노래입니다.
used to show that something is famous or important
She met the president of the company.
그녀는 회사 사장을 만났다.