A.humidityB.varying densities of waterC.vessel trafficD……

单项选择题Vessels，（）support vessels，should not enter the safety zone of a deepwater port unless clearance has been obtained from the Vessel Traffic Supervisor.

A.besides
B.excepted
C.otherwise
D.other than

单项选择题The Rules state that vessels may depart from the Rules when（）.

A.there are other vessels in the vicinity
B.operating in a traffic separation scheme
C.engaged in a situation involving more than two vessels
D.necessary to avoid immediate danger

单项选择题Which statement about the Navigation Rules is TRUE?（）.

A.The rules require vessels to comply with Traffic Separation Scheme regulations
B.The rules use the term safe speed
C.The Rules permit a stand-on vessel to take action prior to being in extremis
D.All of the above are correct

单项选择题If a seaplane is not used as a means of transpiration on water but is capable of being used so，it shall（）.

A.be regarded as a vessel not under command
B.be regarded as a vessel underway
C.be regarded as a vessel
D.be regarded as a sailing vessel

单项选择题If a vessel is engaged in fishing according to the definitions in the Rules，it will have （）.

A.gear extending from the side or stern
B.gear that restricts maneuverability
C.less than 50 percent trolling lines
D.None of the above