99色精品-9色在线-99色在线-99色视频 国产欧美日产一区二区三区_亚洲精品亚洲人成在线观看_四虎在线精品永久观看_免费一级a一片久久精

單項選擇題

The stability of a vessel is normally the greatest when all fuel and water tanks are full because the ().

A.center of gravity is lowered
B.center of buoyancy is lowered
C.reserve buoyancy is unchanged
D.hull freeboard is increased

微信掃碼免費搜題