A dirt biker leaps through the air.
The biker is on the ground.
The dirt biker is in the air while the other biker is on the ground.
exists e1 x1 x2 x3.(n_air(x3) & through(e1,x3) & Actor(e1,x1) & v_leap(e1) & n_biker(x1) & of(x1,x2) & n_dirt(x2))
exists p1 x1 x2.(n_ground(x2) & n_biker(x1) & on(x1,x2))