The word “Mayday” spoken at the start of a transmission identifies _______ .
A.a call for help
B.a distress message
C.an urgency message
D.a radio failure
正确答案是B
The word “Mayday” spoken at the start of a transmission identifies _______ .
A.a call for help
B.a distress message
C.an urgency message
D.a radio failure
正确答案是B