变压器大盖沿气体继电器方向坡度为2%~4%。
参考答案:错
Peter could hardly see the words on the blackboard,______________? [ ]
A. did he
B. couldn't he
C. didn't he
D. could he
电力负荷按物理性能分类是( )。
A.有功负荷; B.机械负荷; C.电炉负荷; D.无功负荷。