기존에 개발된 콘텐츠를 바탕으로 사전 학습동영상을 제공해야 하는데 그 내용도 광범위하고 화질이 좋지 않아 사용하기 힘든 동영상도 많았다.
Based on the previous content, pre-learning videos should be provided but there were many videos that were difficult to use because the content was too extensive and quality was poor.