单项选择题
（）is not a part of the main switch board.
A.Control panel of main generator B.Control panel of emergency generator C.Paralleling panel D.Load panel of main generator
单项选择题 （）are supplied by main switchboard directly.
单项选择题 After resolving the trouble of main power supply, main switch of emergency generator should（）, if power supply is refreshed.
单项选择题 Emergency generator is installed on board mainly to （）
