单项选择题
In the navigation, cause the shafting over load most easily（）
A.stopping the main engine suddenly B.changing the main engine running direction suddenly C.the sailing from the shallow water area to the deep water area D.the ship’s trim too much
单项选择题 The oil index of main engine should be controlled to prevent it from in heavy weather（）
单项选择题 A dry-type spark arrestor removes sparks from a diesel engine exhaust by（）
单项选择题 When the ship is going to enter into the harbor,（）
