A runway used for non-precision instrument approach is usually marked by _______ .
A.the runway number
B.a dashed white centerline
C.threshold markings
D.all the above
正确答案是D
A runway used for non-precision instrument approach is usually marked by _______ .
A.the runway number
B.a dashed white centerline
C.threshold markings
D.all the above
正确答案是D