基本工作时间由作业时间和（）构成。 ["A.生理宽放时间","B.宽放时间","C.加班时间","D.疲劳宽放时间"]
试说明电力架空裸导线型号LGJ-185/25各字母、数字含义。
Atmospheres laden with coal dust or grain dust caused by loading these cargoes（）. ["require loading operations to be shut down until the atmosphere clears","are toxic to human life","are subject to spontaneous combustion","may be explosive in some concentratio"]
重合器主要有哪几种？工作原理分别是什么？
开关操动机构主要有哪几种？有何优缺点？
杆塔按用途分为哪几类？各有何特点？
