单项选择题
In the presence of external forces，the center of buoyancy of an inclined vessel is vertically aligned with the（）.
A.center of gravity B.metacenter C.center of flotation D.keel
单项选择题 Increasing free surfaces has the effect of raising the（）.
单项选择题 Increasing the number of slack liquid tanks has the effect of raising the（）.
单项选择题 Initial stability is indicated by（）.
