A1
에 — to, at, and when
How the Korean particle 에 marks destination, static location and points in time, and how it differs from 에서.
에 marks a destination, a static location, or a point in time. One form, no consonant-vowel pairing.
Destination
학교에 가요.
Hakgyoe gayo.
I go to school.
Where something is
Only with 있다, 없다 and a few verbs of being — see 있다.
집에 있어요.
Jibe isseoyo.
I’m at home.
A point in time
세 시에 만나요.
Se sie mannayo.
Let’s meet at three.
월요일에 시작해요.
Woryoire sijakaeyo.
It starts on Monday.
Relative time words take no particle: 오늘, 내일, 어제, 지금.
내일에 갈 거예요.
내일 갈 거예요.
내일 is relative to now and needs no 에. The same goes for 오늘, 어제, 지금 and 매일.
에 against 에서
The distinction that matters. 에 is where something is or where you are going; 에서 is where something happens.
도서관에 있어요.
Doseogwane isseoyo.
I’m in the library.
도서관에서 공부해요.
Doseogwaneseo gongbuhaeyo.
I study in the library.
Same library, different particle, because the second sentence has an activity in it. See 에서.
Also the receiver
For people, though 에게 or 한테 is used rather than plain 에.
친구한테 전화해요.
Chinguhante jeonhwahaeyo.
I phone my friend.
한테 is the spoken form; 에게 is written. A plain 에 is for places and things — 회사에 연락해요.