单项选择题
Floors aboard ship are（）.
A.also called decks B.vertical transverse plates connecting the vertical keel with the margin plates C.large beams fitted in various parts of the vessel for additional strength D.found in passenger and berthing spaces only
单项选择题 Floors aboard ship are（）.
单项选择题 Frames to which the tank top and bottom shell are fastened are called（）.
单项选择题 Freeing ports on a vessel with soild bulwards（）.
