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
알킬 그룹은 유기 화합물에서 중요한 역할을 합니다.Alkil geurup-eun yugi hwahampul-eseo jungyohan yeoghal-eul hamnida.The alkyl group plays an important role in organic compounds.