单项选择题
A.a combustible element, fuel B.energy (resources for ignition) to start the combustion C.oxygen to support the combustion D.both A and C are correct
Which system(s) in the hydraulic systems of crane alway...
单项选择题Which system(s) in the hydraulic systems of crane always hold(s) single side of load?（）
A.hoisting system only B.hoisting system and luffing system C.hoisting system and slew and slewing system D.slewing system only
Crude oil washing of cargo tanks has the following adva...
单项选择题Crude oil washing of cargo tanks has the following advantages except for （）
A.reducing the erosion of the cargo tanks B.increasing the total quantity of oil to carry C.reducing the quantity of water contained in oil D.reducing cargo discharged time
Where is the cooling water from the compensating tank i...
单项选择题Where is the cooling water from the compensating tank in the cooling water system of main engine lead to?（）
A.discharge side of the centrifugal pump B.suction side of the centrifugal pump C.the lowest point of the cooling water system D.inlet of the main engine
