雷达设备失效时,雷达管制员应当立即通告所有航空器雷达管制服务终止并实施()管制间隔。
A.雷达
B.雷达监控
C.程序
D.目视
参考答案:C
Please don't stand up in class until you .
A.were told to
B.are told to
C.were told
D.are told
封炉后送风,送风风口位置应选在()附近。