问题：
[单选] When the fuel oil is burning in the combustion chamber, it （）.
gives up large amount of heat。gives off large amount of heat。gives up large amount of steam。gives off large amount of steam。
问题：
[单选] （） into the cylinder because no fuel can burn （） it.
Air must be admitted；without。Oil must be injected；without。Air must be admitted；with。Oil must be injected；with。
问题：
[单选] The （） can tell us how much heat we can get from the burning of an oil.
viscosity。flash point。cetane number。calorific value。
问题：
[单选] If the temperature drops low enough, oil will not flow, （） just tell us the temperature.
Hash point。Viscosity。Pour point。Cetane number。
问题：
[单选] In the closed cooling system, the water （）.
is made to circulate out of the system。is made to circulate within the system。is made circulate within the system。is made circulate out of the system。
问题：
[单选] The most important factor that causes the wear of the engine parts is （）.
excessive heat。friction。oxidation。high pressure。
问题：
[单选] The lube oil to lubricate the surfaces of the cylinder liners is spread over by the （）.
sliding piston rings。engines camshaft。small pumps。forced feed system。
问题：
[单选] Impurities in the fuel oil will affect the operation of the engine, which has （） the use of separator and some other devices.
brought about。caused for。resulted from。led。
问题：
[单选] The emulsion of the oil is mainly caused by （）.
the solid impurities of large particle。the solid impurities of fine particle。the water content。both water and solid impuritie。
问题：
[单选] A decrease in the flash point of diesel engine lube oil indicates the lube oil has become （）.
contaminated with sludge。contaminated with carbon。diluted with fuel oil。diluted with water。
