—Heathrow Ground, GACDK. —_______ calling Heathrow Ground, say again your call sign.
A.GACDK
B.Aircraft
C.Station
D.either B or C
正确答案是D
—Heathrow Ground, GACDK. —_______ calling Heathrow Ground, say again your call sign.
A.GACDK
B.Aircraft
C.Station
D.either B or C
正确答案是D