An azimuth angle for a body is measured from the（）.

单项选择题An authorized light to assist in the identification of submarines operating on the surface is a(n)（）.

A.blue rotating light
B.intermittent flashing amber/yellow light
C.flashing white light
D.flashing sidelight

单项选择题An aneroid barometer on a boat should always be（）.

A.located in an air-conditioned area
B.mounted in the passenger compartment
C.protected by a collision bulkhead
D.permanently mounted

单项选择题An anchored vessel is servicing an aid to navigation and is restricted in her ability to maneuver. Which lights will she show? （）

A.Three lights in a vertical line，the highest and lowest red and the middle white，and anchor lights
B.Three lights in a vertical line，the highest and lowest red and the middle white，ONLY
C.Anchor lights ONLY
D.Anchor lights and sidelights ONLY

单项选择题An all-round flashing yellow light may be exhibited by a(n)（）.

A.vessel laying cable
B.vessel towing a submerged object
C.vessel not under command
D.air cushion vessel

单项选择题An airplane should NOT send which signal in reply to a surface craft?（）

A.Opening and closing the throttle
B.Rocking the wings
C.Flashing the navigational lights off and on
D.Flashing Morse T