单项选择题
In ship construction，keel scantlings should be the greatest（）.
A.at each frame B.amidships C.one-third the distance from the bow D.one-third the distance from the stern
单项选择题 In ship construction，frame spacing is（）.
单项选择题 In relation to cargo gear，what does SWL mean?（）.
单项选择题 In nautical terminology a dog is a（）.
