A windsurfer surfs on frothy waves.
A person is laying on the beach.
One may not be surfing on water and laying on a beach at the same time
exists e1 s1 x1 x2.(on(e1,x2) & n_wave(x2) & a_frothy(s1) & Theme(s1,x2) & Actor(e1,x1) & v_surf(e1) & n_windsurfer(x1))
exists e1 x1 x2.(n_beach(x2) & on(e1,x2) & Actor(e1,x1) & v_lay(e1) & n_person(x1))