单选题If several fixed navigational lights are visible at the same time，each one may be positively identified by checking all of the following EXCEPT what against the Light List?（）A RhythmB PeriodC IntensityD Color

A mobile offshore drilling unit must display obstruction lights when it is on the waters over the Outer Continental Shelf and is ______.

A.under tow

B.fixed to the seabed

C.underway

D.All of the above

A vessel may exhibit lights other than those prescribed by the Rules as long as the additional lights ______.

A.are not the same color as either side light

B.have a lesser range of visibility than the prescribed lights

C.do not impair the visibility or distinctive character of the prescribed lights

D.All of the above

Restricted areas at locks and dams are indicated by ______.

A.flashing red lights upstream and fixed red lights downstrem

B.yellow unlighted buoys

C.signs and / or flashing red lights

D.red daymarks upstream and green daymarks downstream

If several fixed navigational lights are visible at the same time, each one may be positively identified by checking all of the following EXCEPT what against the Light List?______.

A.Rhythm

B.Period

C.Intensity

D.Color

Many navigational warnings are of a temporary nature，but others remain in force for several months or may be succeeded by ______.

A.Notices to Mariners

B.Sailing Directions

C.List of Lights and Signals

D.Guide to Port Entries

A vessel is approaching from dead ahead.Both of her sidelights are visible and her range lights are in line. Which of the following could you do first? ______.

A.Sound one blast of the whistle

B.Alter course to starboard

C.Construct a radar plot

D.Sound the danger signal

Ink-jet printer belongs to nonimpact printers in which the characters are formed by projecting particles or droplets of ink on to paper.(71) printer is also a nonimpact printer in which the characters are produced by applying hot elements to heat-sensitive paper directly or by melting ink from a(72) on to plain paper. Electrostatic printer creates an electrostatic latent image, which is then made visible by a toner and transferred and fixed on paper. An electrostatic printer may be used in some instances as a(73). Laser printer creates, by means of a laser beam directed on a(74) surface, a latent image which is then made visible by a toner and transferred and fixed on paper. Magnetographic printer creates, by means of magnetic heads operating on a metallic drum, a latent image which is then made visible by a toner and transferred and fixed on paper. Computer-output-microfilm (COM) printer produces on a photographic film a(75) of each page.

A．Hot

B．Warm

C．Heat

D．Thermal