This is the 371st most frequent Korean word.
문제는
"The problem is" or "The issue is."
The word '문제는' here emphasizes a specific concern or problem to be discussed.
문제는 왜 이런 일이 자꾸 반복되는지에 있습니다.
The issue is why such things keep happening repeatedly.
In this sentence, '문제는' introduces a challenge or obstacle to be considered.
문제는 이 계획이 예상보다 더 많은 자원을 요구한다는 점입니다.
The problem is that this plan requires more resources than expected.
Here, '문제는' highlights a particular difficulty faced by the students.