A．Because they can fly very high.B．Because they can carry larger freight over within a shorter time.C．Because they are the newest form of transport.D．Because they can go somewhere that cannot be reached by other transports.
A．Because they can fly very high.
B．Because they can carry larger freight over within a shorter time.
C．Because they are the newest form of transport.
D．Because they can go somewhere that cannot be reached by other transports.