A/V-던 grammar = used to, V-ed ~(1) recollect a past repeated action or (2) recall an action started in the past but has not ended yet

A/V-던 grammar = used to, V-ed ~ (1) recollect a past habit or repeated behavior, (2) recall an action or behavior started in the past but has not ended yet.

Usage:

- (1) A/V-던 is used to recollect a past action or habit that was repeated often in the past but not continued to present = used to 

여기가 제가 어릴 때 다니던 학교예요.

This is the school I used to go when I was young.

- (2) V-던 is also used to recall an action or behavior started in the past but has not ended yet = V-ed

아침에 읽던 신문을 어디에 뒀지?

Where did I put the newspaper I read this morning? (I haven't finished reading it yet.)

- A/V-았/었던 is used to recall a past event that has not continued to present. (Read V-았/었던 grammar for details)

Tense:

Verb + -던 = used to 

가다 -> 가던 (used to go)

보다  -> 보건 (used to see)

살다 -> 살던 (used to live)

공부하다 -> 공부하던 (used to study)

사용하다 -> 사용하던 (used to use)

방문하다 -> 방문하던 (used to visit)

Adjective + 던 = used be 

크다 -> 크던 (used to be big)

아프다 -> 아프던 (used to be sick)

작다 -> 작던 (used to be small)

유명하다 -> 유명하던 (used to be famous)

Examples:

*A/V-던 grammar = used to ~ recollect a past repeated action

1. 라면은 제가 예전에 자주 먹던 음식이에요.

Ramen is a food I used to eat often.

2. 예전에 자주 아프던 아이가 요즘은 건강해요.

The child used to be sick in the past is now healthy.

3. 옆집 살던 사람은 지난 주말에 이사했어요.

The person that used to live next door moved in last weekend.

4. 이 노래는 제가 대학생 때 자주 듣던 노래예요.

This is a song that I used to listen when I was a student.

5. 이 자전거는 형이 학교에 다니던 거예요.

This is the bike that my older brother used to go to the school.

6. 길을 밝히던 불이 꺼지고 나서 길이 어두워졌어요.

The light that used to brighten the street went out and the street became dark.

7. 왜 전에 공부하던 책을 계속 공부해요?

Why are you still studying that book you already studied before?

8. 방금 들어온 사람은 우리 가게에 자주 오던 손님이에요.

The person who just came in is a frequent customer to our store.

9. 이 책은 아주 오래된 책 같아요.
- 맞아요. 제가 고등학생 때 공부하던 책이에요.

This book seems really old.
- You’re right. It’s a book I used to study when I was a high school student.

10. 어제 드라마를 안 봐요?
- 네, 재미있게 보던 드라마가 지난주에 끝나 버렸거든요.

Don’t you watch drama yesterday?
- Yes, I don’t. Because the interesting drama I used to watch ended last week.

*V-던 grammar = V-ed ~ recall an action started in the past but has not ended yet

1. 어제 본 영화를 아직 끝까지 못 봐서 계속보고 싶어요.

-> 어제 보던 영화 계속 볼까?  

I still want to watch the movie I saw yesterday because I haven't seen it to the end yet.

-> Shall we continue watching the movie we watched yesterday?

2. 어제 지훈이 읽는 책을 봤는데 재미있어 보였어요. 그래서 그 책을 빌려서 읽고 싶어요.

-> 지훈아, 어제 네가 읽던 책 좀 빌려 줄래?

I saw the book Jihoon was reading yesterday and it looked interesting. So I want to borrow that book and read it.

-> Jihoon, can you lend me the book you read yesterday?

3. 빵을 먹다가 잠깐 통화를 하고 왔어요. 그런데 빵이 없어졌어요.

-> 내가 먹던 빵 어더에 있어?

While eating bread, I got a phone call for a while. But the bread was gone.

-> Where is the bread I was eating?

4. 오늘도 많이 바빠? 

- 응, 어제 하던 숙제를 다 끝내야 해.

Are you very busy today?

- Yes, I have to finish all the homework I was doing yesterday.

5. 그것은 제가 오전에 마시던 커피예요.

That's the coffee I drank in the morning. (I haven't finished drinking yet)

Specific usage:

1. If the action or behavior used to do in the past but not anymore at present, 여러 번, 자주, 가끔, 항상 are often used.

우리가 자주 가던 공원에 다시 가 보고 싶어요. 

I want to go to the park that we often went.

2. If the action or behavior started in the past but has not ended yet, 지난달, 지난주, 어제, 아까, 저번에 are often used.

아까 내가 사용하던 종이컵을 버렸어요? 

Did you throw away the paper cup I was using earlier?

3. The expression is not used for action or behavior that only occurred once and do not repeat.

이곳은 제가 결혼하던 곳이에요. (wrong) / 이곳은 제가 결혼한 곳이에요. (correct)

This is the place where I got married.

Comparison between V-던 and V-(으)ㄴ grammar

1. V-던: Express a past behavior that has not ended yet or repeatedly done in the past

E.g. 어제 읽던 책을 어디에 두었지? 

The speaker has not finished reading the book.

2. V-(으)ㄴ: Express a past behavior that has ended or without repetition.

E.g. 어제 읽은 책의 제목이 생각 안 나요? 

The speaker finished reading the book yesterday.