单项选择题
A.fix B.dead-reckoning position C.running fix D.probable position
A polyconic projection is based on a （）.A.plane tangent...
单项选择题A polyconic projection is based on a （）.
A.plane tangent at one point B.cylinder tangent at one parallel C.cone tangent at one parallel D.series of cones tangent at selected parallels
A pilot vessel on pilotage duty at night will show side...
单项选择题A pilot vessel on pilotage duty at night will show sidelights and a stern light （）.
A.when at anchor B.only when making way C.at any time when underway D.only when the identifying lights are not being shown
A pilot vessel may continue to sound an identity signal...
单项选择题A pilot vessel may continue to sound an identity signal if she is （）.
A.aground B.at anchor C.not under command D.being towed
