D类空域内,放行仪表飞行的同速航空器,同航迹同高度()分钟间隔。
A.2
B.3
C.5
D.10
参考答案:D
—Hello! May I speak to Mr. Smith?
—________. I'll go and get him. [ ]
A. Speaking
B. Wrong number
C. Hold on, please
无线抄表系统的特点。