单项选择题
A.water B.oil C.heat D.steam
Impurities from the boiler water surface can be removed...
单项选择题Impurities from the boiler water surface can be removed through the （）.
A.safety valve B.blow down valve C.scum valve D.feed check valve
All bilge suction must be fitted with suitable （）, whic...
单项选择题All bilge suction must be fitted with suitable （）, which in the machinery space would be mud boxes positioned at floor-plate level for easy access.
A.strainers B.valves C.elements D.separators
Centrifugal pumps, however, can be designed with a numb...
单项选择题Centrifugal pumps, however, can be designed with a number of impellers （） to attain a large amount of liquid.
A.in series B.in parallel C.assembled D.together
