공부하느라

In a sentence

• 아침부터 공부하느라 정신이 없었어요.

  I was busy studying since this morning.

  The phrase "공부하느라" is used here to indicate the reason for being busy.

• 친구에게 선물 사러 가지 못했는데, 공부하느라 시간이 없었어요.

  I couldn't go buy a gift for my friend because I didn't have time due to studying.

  "공부하느라" is employed to explain the cause of not having time.

• 밤새 공부하느라 요즘 잠이 부족해요.

  I haven't been getting enough sleep lately because I studied all night.

  Here, "공부하느라" expresses the activity of studying as the reason for insufficient sleep.