单项选择题
If the water level dropped rapidly in the expansion tank of a closed diesel engine cooling water system, you should suspect a （）
A.loss of suction in the circulating pump B.leak in the primary cooling system C.broken raw water pump shaft D.burned or cracked piston in one cylinder
单项选择题 To minimize the formation of carbon deposits on fuel injection nozzles, you should （）
单项选择题 In a simple mechanical governor, the （）
单项选择题 If a diesel engines exhaust temperature is abnormally high, the cause could be（）
