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
석탄의 분해증류 과정은 다양한 화학 물질을 생성합니다.seoktanui bunhaejeungnyu gwajeong-eun dayanghan hwahak muljil-eul saengseonghamnida.The process of destructive distillation of coal produces various chemical substances.