单项选择题
The radio waves used for radar are very short，only（）long.
A.a few centimeters
B.a few fathoms
C.a few meters
D.a few feet
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相关考题
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单项选择题
The radar control used to reduce sea return at close ranges is the（）.
A.gain control
B.sensitivity time control
C.fast time constant
D.pulse length control -
单项选择题
The radar control that shortens all echoes on the display and reduces clutter caused by rain or snow is the（）.
A.sensitivity time control (sea clutter control)
B.receiver gain control
C.brilliance control
D.fast time constant (differentiator) -
单项选择题
The radar control that reduces weak echoes out to a limited distance from the ship is the（）.
A.sensitivity time control (sea-clutter control)
B.receiver gain control
C.brilliance control
D.fast time constant (differentiator)
