The airway width in China is usually ______ km, and due to some constraints can be reduced to, but not less than ______ km.
A.20 10
B.20 8
C.15 10
D.10 8
正确答案是B
The airway width in China is usually ______ km, and due to some constraints can be reduced to, but not less than ______ km.
A.20 10
B.20 8
C.15 10
D.10 8
正确答案是B