单项选择题
A position obtained by crossing lines of position taken at different times and advanced to a common time is a(n)（）.
A.running fix B.dead-reckoning position C.fix D.estimated position
单项选择题 A position obtained by applying only your vessel’s course and speed to a known position is a （）.
单项选择题 A line of position is（）.
单项选择题 A line connecting all possible positions of your vessel at any given time is a（）.
