A man is sitting on a silver scooter.
A man is sitting on a moving scooter.
We don't know if the scooter is moving or not, you can sit on a scooter when it is still also.
exists e1 x1 x2 x3.(on(e1,x2) & n_scooter(x2) & of(x2,x3) & n_silver(x3) & Actor(e1,x1) & v_sit(e1) & n_man(x1))
exists e2 e1 x1 x2.(on(e1,x2) & n_scooter(x2) & Actor(e2,x2) & v_move(e2) & Actor(e1,x1) & v_sit(e1) & n_man(x1))