"Accoring to the three ways of picture presentation in the text, respectively, the movement of displayed echoes is shown with respect to the following except ___.
A.the observing vessel
B.the water
C.the ground
D.the navigational signals"
正确答案是D
"Accoring to the three ways of picture presentation in the text, respectively, the movement of displayed echoes is shown with respect to the following except ___.
A.the observing vessel
B.the water
C.the ground
D.the navigational signals"
正确答案是D