bu backunuitbu backuunitstand by device备用: reserve; spare; alternate; b ...器件: device; parts of an apparatu ...器件: device; parts of an apparatus or appliance; component 电子器件 electronic device备用: reserve; spare; alternate; backup; standby application; standby分用器: demultiplexer demux下载手机词典可随时随地查词查翻译