A. 外部引荐 B. 外部营销 C. 内部营销 D. 内部引荐
A. induce carbon formation on cylinder walls B. improve fuel penetration in the combustion space C. form a friction reducing film between mating surfaces D. lubricate the fuel injectio
A. 技术性变动成本 B. 酌量性变动成本 C. 半变动成本 D. 延期变动成本