单项选择题
On engines having oil cooled pistons the lubricating oil pre-heater must be put into operation and the rate of heating so （） that the temperature of the piston cooling oil returns are 32℃ to 35℃ over a period of at least two hours.
A.slow
B.quick
C.arranged
D.high
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相关考题
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单项选择题
Too much excess air is （）because the heat generated is being lost through the exhaust trunking instead of being made used of in heating the water to produce steam.
A.not good
B.good
C.better
D.the best -
单项选择题
（） the oxygen content in the exhaust gas, （） the combustion is.
A.The lower；the worse
B.The higher；the better
C.The lower；the better
D.The highest；the worst -
单项选择题
Injectors on modern engines are cooled by a combination of the intensive bore cooling in the cylinder by a combination of the intensive bore pockets and by the fuel which is re-circulated through the injector when the follower is on the （）of the cam or when the engine is stopped.
A.slope
B.base
C.top
D.bottom
