单项选择题
A.distribution boards B.section boards C.emergency switch boards D.main switch boards
UMS stands for（）.A.ultra much spaceB.universal medium s...
单项选择题UMS stands for（）.
A.ultra much space B.universal medium system C.unit machined space D.unattended machinery space
Oil mist detectors are usually used on board to detect ...
单项选择题Oil mist detectors are usually used on board to detect oil mist density within （）.
A.the engine crankcase B.the engine scavenge boxes C.drain tanks D.fuel tanks
A viscosity regulator used for an engine is usually pro...
单项选择题A viscosity regulator used for an engine is usually provided in order to （） for an engine burning heavy fuel oil.
A.regulate the fuel supply B.maintain a constant fuel viscosity at the fuel valves C.maintain efficient cooling D.alter the fuel density
