This is the 587th most frequent Korean word.
열심히
Diligently.
In this sentence, '열심히' is used as an adverb to describe how the subject ('he') performed the action of studying ('공부했어요'). It conveys the idea of putting in effort and being diligent in the process.
그는 시험을 준비하면서 열심히 공부했어요.
He studied diligently while preparing for the exam.
Here, '열심히' is utilized to specify the manner in which the students listened ('듣고'). It highlights their active engagement and focus during the listening.
학생들이 열심히 듣고 질문을 했어요.
The students listened attentively and asked questions.
'열심히' in this instance is modifying the action of practicing running ('달리기 연습을 해서'), underlining the dedicated effort and commitment which led to her success.