A virtual rise in the center of gravity may be caused by ______.
A.filling a partially filled tank
B.using an on board crane to lift a freely swinging heavy object
C.emptying a partially filled tank
D.transferring ballast from the forepeak to the after peak
正确答案：B
使用船吊起吊自由摇摆的重物可能导致实际重心高度升高
