单项选择题
（）is power supplied by main switchboard directly not through sub-board.
A.Deck machinery B.Little power load C.Some important load D.stationary submersible pump
单项选择题 （）are located on the road panel of main switchboard.
单项选择题 Insulation light is located on.（） of main switchboard.
单项选择题 Synchrocope and synchro light are located on （） of main switchboard.
