99色精品-9色在线-99色在线-99色视频国产欧美日产一区二区三区_亚洲精品亚洲人成在线观看_四虎在线精品永久观看_免费一级a一片久久精

<pre id="ljhhk"><legend id="ljhhk"></legend></pre>

<ruby id="ljhhk"></ruby>

<dd id="ljhhk"></dd>

<sup id="ljhhk"><pre id="ljhhk"><div id="ljhhk"></div></pre></sup>

單項選擇題

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

你可能感興趣的試題

單項選擇題

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

單項選擇題

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)

<ruby id="lhcsl"><output id="lhcsl"></output></ruby>