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(xiàng)選擇題

The possibility of damage from operating a diesel engine at critical speeds is reduced by the use of().

A.an isochronous governor
B.elastic engine mounts
C.a vibration damper
D.a cast iron bed plate with good flexible qualities

微信掃碼免費(fèi)搜題