单项选择题
A.concentrated high and the double bottoms empty
B.concentrated low and the double bottoms empty
C.evenly distributed vertically with the double bottoms full
D.concentrated and with the double bottoms full
单项选择题 A tank which carries liquid is dangerous to the stability of a vessel when it is（）.
单项选择题 A semisubmersible which will not remain upright and will assume a list either to port or starboard is likely to have（）.
单项选择题 A disk with a horizontal line through its center，equivalent to the summer load line，is called the（）.