A motorcycle rider wearing black and silver does a wheelie on a sandy terrain.
A bike rider is riding on sand.
A motorcycle is considered a bike and sandy terrain implies that the terrain is covered in sand, therefore a bike rider is riding on sand.
exists e1 e2 s1 s2 x1 x2 x3 x4 x5 x6.(on(e2,x6) & n_terrain(x6) & a_sandy(s2) & Theme(s2,x6) & Theme(e2,x5) & Actor(e2,x1) & v_do(e2) & n_wheelie(x5) & Theme(e1,x4) & Actor(e1,x3) & v_wear(e1) & n_silver(x4) & a_black(s1) & Theme(s1,x4) & (x1 = x3) & n_rider(x1) & of(x1,x2) & n_motorcycle(x2))
exists e1 x1 x2 x3.(on(e1,x3) & n_sand(x3) & Actor(e1,x1) & v_ride(e1) & n_rider(x1) & of(x1,x2) & n_bike(x2))