The airspeed required to sustain an aircraft in straight and level flight depends on _______ .
A.the flap position
B.the angle of attack
C.the weight
D.all the above
正确答案是D
The airspeed required to sustain an aircraft in straight and level flight depends on _______ .
A.the flap position
B.the angle of attack
C.the weight
D.all the above
正确答案是D