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

In ship construction,frame spacing is().

A.greater at the bow and stern
B.reduced at the bow and stern
C.uniform over the length of the vessel
D.uniform over the length of the vessel,with the exception of the machinery spaces,where it is reduced due to increased stresses

微信掃碼免費(fèi)搜題