控制室、开关室、计算机室等通往（）等处的所有电缆孔洞和盘面之间的缝隙（含电缆穿墙套管与电缆之间缝隙）必须采用合格的不燃或阻燃材料封堵。
A. 电缆夹层、隧道
B. 穿越楼板
C. 墙壁
D. 控制柜、盘
查看答案
Before the sludge in a purifier is ejected,（）
A. the oil feeding is stopped and replaced by admitting flushing water
B. the flushing water feeding is stopped and replaced by admitting oil
C. the feeding of dirty oil and flushing water is stopped
D. the feeding of dirty oil and flushing water is admitted
营业人员（）佩戴工号牌，或在柜台前放置工号牌。
A. 营业时
B. 服务时
C. 上岗时
D. 收寄时
微信支付 
支付宝支付