单项选择题
A.difference between the vessel's speed through the water at any instant and the new speed ordered on the telegraph
B.distance the vessel has actually run through the water since a change of speed was ordered
C.distance the vessel will run between taking action to stop her and being stationary in the water
D.speed at which a vessel should proceed to ensure that she will run a predetermined distance，once her engines have been stopped
单项选择题 If you do NOT understand the course or intention of an approaching vessel you should sound （）.
单项选择题 If the PSCO from general impressions or observations on board has（）for believing that the ship，its equipment or its crew do not substantially meet the requirements，the PSCO should proceed to a more detailed inspection.
单项选择题 If a ship is proceeding towards the magnetic equator，the uncorrected deviation due to permanent magnetism（）.