单项选择题
A.The marine sextant B.The chronometer C.The magnetic compass D.The gyrocompass
（）is used for measuring horizontal and vertical angles....
单项选择题（）is used for measuring horizontal and vertical angles.
A.The marine sextant B.Thechronometer C.The magnetic compass D.The gyrocompass
（）means rudder to be held in the force and aft angles.A...
单项选择题（）means rudder to be held in the force and aft angles.
A.Steady B.Meet her C.Midships D.Stop engines
（）means check the swing of the vessel’s head in a turn....
单项选择题（）means check the swing of the vessel’s head in a turn.
