【判断题】照明设备所采用的导线型号及敷设方式通常根据电压高低而定。
【简答题】( )的备用方式通常分为明备用和暗备用两种。
【单选题】They didn't discover until they happened to enter the back room ______ someone had stolen the priceless painting. [ ]
【单选题】The writer was so ______ on her work that she didn’t notice him enter the room
【简答题】( )的备用方式通常分为明备用和( )备用两种。