As the picture shows, Xiaohua takes the A train and sees the B train outside the window. Try to judge whether the following statement is correct according to the picture () A. Take the ground as a ref

As the picture shows, Xiaohua takes the A train and sees the B train outside the window. Try to judge whether the following statement is correct according to the picture () A. Take the ground as a reference. A, with the ground as the reference, train B is moving, or it may be stationary, so A is wrong;

B, as can be seen from the figure, the positions of the two cars are changing, so train A is the reference, and train B must be moving, so b is correct;

C as can be seen from the figure, the positions of the two cars are changing. Taking train B as a reference, train A must be moving, so C is wrong;

D. Taking the ground as a reference, two trains may be moving, or one train may be stationary, so D is wrong.

So choose B.