A man is sky surfing on the water.
A man is sky diving.
Surfing is not the same as diving.
exists p1 x1 x4.(n_water(x4) & exists e1 x2 x3.((x1 = x2) & on(e1,x4) & Actor(e1,x3) & v_surf(e1) & (x2 = x3) & n_sky(x2)) & n_man(x1))
exists p1 x1.(exists x2 x3.((x1 = x2) & n_diving(x2) & of(x2,x3) & n_sky(x3)) & n_man(x1))