97免费在线观看视频,亚洲综合自拍网,黄色毛片免费观看,热久久综合网,免费看日产一区二区三区 狠狠操av,久久久涩涩涩,在线精品免费视频,人人插天天干,久久91精品国产91久久

單項選擇題

()diesel engines generally have two systems of lubrication:()a total loss system feeding and a circulating system lubricating the running gear and cooling the pistons.

A.Large crosshead type;crossheads
B.High speed;the cylinders
C.Large crosshead type;the cylinders
D.Four-stroke;pistons and cylinders

微信掃碼免費搜題