临边防护栏杆采用钢筋作杆件时,上杆直径不应小于16mm,下杆直径不应小于14mm,栏杆柱直径不应小于()
A.14mm
B.16mm
C.18mm
D.20mm
参考答案:C
In our class there are _____ boy students.[ ]
A. three-thirty
B. thirty three
C. thirty-three
对电气设备特殊巡视的内容有哪些?