单项选择题
The inner bottom is the（）.
A.tank top B.compartment between the tank top and shell of the vessel C.inner side of the vessel's shell D.space between two transverse bottom frames
单项选择题 The flood stream here is at an average rate of 0.8（）.
单项选择题 The construction portfolio may be included as part of the ship（）.
单项选择题 The circular steel structure installed around the propeller of a towboat is the（）.
