单项选择题
PPI is（）.
A.a plan-position indicator system B.pulse-plan integration C.pulse-pulse input D.power-plan input
单项选择题 Although manual plotting for CPA works well，the workload can become overwhelming when confronted with（）.
单项选择题 （）typically extends from close as 0.1 nautical miles out to 32 NM.
单项选择题 （）is not used in modern radar.
