等级评价法
情报学与信息管理学
Why will a switch never learn a broadcast address?（） [" Broadcast frames are never sent to swiches."," Broadcast addresses use an incorrect format for the switching table."," A broadcast address will never be the source address of a frame."," Broadcasts only use network layer addressing."," A broadcast frame is never forwarded by a switch."]
西方文化的精髓是：（） ["科学，民主，立宪","自由，平等，博爱","解放，立宪，法制","法制，民主，平等"]
脊线
骨龄
