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
활성탄은 물의 불순물을 제거하는 데 사용됩니다.hwalseongtan-eun mul-ui bulsunmul-eul jegeo-haneun de sayongdoemnida.Activated carbon is used to remove impurities from water.