单项选择题
The emergency generator or emergency battery is connected to（） on most large ships.
A.distribution boards B.section boards C.emergency switch boards D.main switch boards
单项选择题 The main generators are connected to（）.
单项选择题 UMS stands for（）.
单项选择题 Oil mist detectors are usually used on board to detect oil mist density within （）.
