The pistons are cooled by oil supplied from the forced （） system.

[单选题]Oil is supplied to the cylinder wall and （） by means of mechanical lubricators.A . the cylinder coverB . the piston ringsC . the piston crownD . the piston skirt

[单选题]Lubricating oil is supplied to the crank-pin bearings in a marine diesel engine by （）.A . internal crankshaft passagesB . immersion in oilC . splash lubricationD . injection lubricatio

[单选题]The engine is started with （） supplied from air receivers.A . pressure oilB . pressure waterC . compressed airD . cooling water

[单选题]The pressurized air is usually cooled to increase the charge air （）.A . viscosityB . densityC . velocityD . electricity

[单选题]________is supplied with electricity by main switchboard directly not through sub-board on boardA．Deck machineryB．Little power loadC．Some important load machineryD．Stationary submersible pump

[单选题]F．or _______the power is supplied by main switchboard directly not through sub-boardA．saving network costB．improving the reliability of supplying power to important loadC．preventing sequence reversingD．increasing the power Factor of important load

[单选题]The compressed air is supplied by （） to the air reservoirs.A . compressorsB . forced fansC . ventilatorsD . generator

[单选题]Fuel is not supplied to the corresponding cylinders due to （）.A . a failure of the motorB . a failure of lubricatorC . a failure of cylinderD . a failure of fuel pum

[单选题]（） provide the water to the pistons.A . Pneumatic pipesB . Hydraulic pipesC . Telescopic pipesD . Operating gas pipe

[单选题]Aluminum pistons have （） coefficient of thermal expansion compared with those of cast iron.A . higherB . lowerC . the sameD . none of the above