单项选择题
If the weights are concentrated in the middle part，then（）will happen on board the ship.
A.hogging B.stiffness C.sagging D.listing
单项选择题 If a vessel is sagging，what kind of stress is placed on the sheer strake?（）
单项选择题 Frames to which the tank top and bottom shell are fastened are called（）.
单项选择题 Floors aboard ship are（）.
