同一材料导体的电阻和它的截面积成反比。
参考答案：对
The Chief Petty Officer employed in the repair and maintenance work shall such abilities as to prepare and apply（）.
A.primers and paints
B.painters
C.promisers
D.compromisers
塔筒筒壁的混凝土验算等级不应低于( )。
A．C30 B．C25C．C20 D．C15
