A. a and B B. a and b or C C. a and b and C D. (a or b)and c
A. 油温低时粘度大,油膜厚、承载能力强 B. 油温太高、粘度小、承载能力低 C. 油温太低,流动性能差,可能造成轴承的半干磨擦而出事故 D. 油温越低越好