单项选择题
A change in the degree of fuel atomization in a diesel engine would most greatly affect （）.
A.air turbulence B.fuel penetration C.fuel spray angle D.fuel injection rate
单项选择题 Scale and dirt accumulation in the waterside of a lube oil cooler will be indicated by a gradual increase in the lube oil（）.
单项选择题 The lower section of a piston is called the （）.
单项选择题 The diesel engine valve subjected to most severe conditions of service is the （）.
