When a vessel is in any doubt as to whether such a situation exists she shall（）that it does exist and act accordingly.

单项选择题Vessels should maintain a sharp lookout，especially during December through March，when navigating the right whale’s only known calving grounds which lie off the coasts of（）.

A.Nova Scotia
B.Maine and Massachusetts
C.Georgia and NE Florida
D.California and Mexico

单项选择题Vessel engaged in the launching or recovery of aircraft is called（）．

A.A vessel restricted in her ability to maneuver
B.A vessel not under command
C.A vessel constrained by her draught
D.A vessel not under way

单项选择题Underway at night，a vessel displaying the lights shown is（）.

A.Engaged in fishing
B.Mine sweeping
C.A pilot boat
D.Under sail

单项选择题Under what condition are you allowed to depart from the rules of the road（）.

A.To avoid immediate danger
B.When authorized by the rig superintendent
C.To comply with an operator's requirement
D.Under no conditions

单项选择题Two vessels meeting in a “head-on” situation are directed by the Rules to（）.

A.alter course to starboard and pass port to port
B.alter course to port and pass starboard to starboard
C.decide on which side the passage will occur by matching whistle signals
D.slow to bare steerageway