单项选择题
Shore power must be（） during dock repair.
A.disconnected B.switched off C.cut off D.connected
单项选择题 The coil of wire rotating in the magnetic field produces the（）.
单项选择题 （） is used to produce electric power.
单项选择题 The system will include various （） such as low tank level alarms and remote operation of tank outlet valves in the events of a fire.
