doseogwaneseo gongbuhadaga chinguege yeonrakhaesseoyo.

While studying at the library, I contacted a friend.

Breakdown of doseogwaneseo gongbuhadaga chinguege yeonrakhaesseoyo.

• ~에서: location particle
• 친구: friend
• 도서관: library
• 공부하다: to study

Questions & Answers about doseogwaneseo gongbuhadaga chinguege yeonrakhaesseoyo.

What does -다가 in 공부하다가 mean here?

-다가 links two actions and usually means:

• while doing X
• then Y happened
• often with a feeling that the first action was interrupted or paused

So 도서관에서 공부하다가 친구에게 연락했어요 suggests:

• I was studying at the library,
• and then I contacted my friend.

This is a little different from -고, which is often just a simple and/then connection.

Why is it 도서관에서, not 도서관에?

Because 에서 marks the place where an action happens.

Here, 공부하다 is an action, so the location takes 에서:

• 도서관에서 공부했어요 = I studied at the library.

By contrast, 에 is commonly used for:

• destination: 도서관에 갔어요 = I went to the library
• existence/location with 있다/없다: 도서관에 있어요 = I am in the library

So in this sentence, 에서 is the correct particle.

How is 공부하다가 formed from 공부하다?