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

When used with reversing reduction gears, medium-speed diesel engines should be bolted to their foundations with fitted bolts at the drive end and clearance(loosely fitted) bolts in other locations √This is done to ()

A.maintain alignment when the ship’s hull is working in heavy seas
B.ensure engine vibrations correspond to the natural frequency of the hull
C.permit the engine to expand away from the driven equipment as the engine heats up and expands
D.maintain engine thrust bearing clearances

微信掃碼免費(fèi)搜題