单项选择题
When using horizontal sextant angles of three objects to fix your position，an indeterminate position will result in which situation（）.
A.The objects lie in a straight line B.The vessel is inside of a triangle formed by the objects C.The vessel is outside of a triangle formed by the objects D.A circle will pass through your position and the three objects
单项选择题 When navigating a vessel，you（）.
单项选择题 When latitude and longitude are used，these shall be expressed in（）（and decimals of a minute if necessary），north or south of the Equator and east or west of Greenwich.
单项选择题 What is an ebb current（）.
