单项选择题
A position obtained by applying ONLY your vessel’s course and speed to a known position is a （）.
A.fix B.dead-reckoning position C.running fix D.probable position
单项选择题 A polyconic projection is based on a （）.
单项选择题 A pilot vessel on pilotage duty at night will show sidelights and a stern light （）.
单项选择题 A pilot vessel may continue to sound an identity signal if she is （）.
