Black Friday: lifetime access is on a special offer in the app, until November 30. Black Friday: special offer on lifetime access, until November 30. Download
중수는 원자력 발전소에서 중요한 역할을 합니다.Jungsu-neun wonjaryeok baljeonso-eseo jungyohan yeoghal-eul hamnida.Heavy water plays an important role in nuclear power plants.