单项选择题
If over a period of weeks the air-box pressure of a turbo-charged, diesel engine, operating at full load, appears to be dropping off, the cause can be （）.
A.open air-box drains B.loss of cooling water to the diffuser C.gradual fouling of the air filters D.improperly timed exhaust valves
单项选择题 The most common cause of scale formation in an auxiliary boiler is （）
单项选择题 For proper operation, auxiliary boiler feed water must have which of the following characteristics?（）
单项选择题 If a four-stroke/cycle diesel engine is running at 1550 RPM, the speed of the camshaft will be（）.
