单项选择题
The closest point of approach (CPA) of a contact on a relative motion radar may be determined（）.
A.immediately when the contact is noted on radar
B.only if the radar scope is watched constantly
C.after the contact has been marked at least twice
D.by an occasional glance at the radar
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相关考题
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单项选择题
The articulated light is superior to other types of buoys because（）.
A.the radar reflectors reflect better signals
B.fog horn signals travel farther to sea
C.it is equipped with strobe lights
D.it has a reduced watch circle -
单项选择题
The ARPA may swap targets when automatically tracking if two targets（）.
A.are tracked on reciprocal bearings
B.are tracked at the same range
C.are tracked on the same bearing
D.pass close together -
单项选择题
The 3-cm radar as compared to a 10-cm radar with similar specifications will（）.
A.give better range performance in rain，hail，etc
B.display small targets in a mass of dense sea clutter at a greater range
C.have less sea return in choppy rough seas
D.display a more map like presentation for inshore navigation
