An surfer airborne over a wave.
A person is swimming in still water.
A person cannot be swimming and surfing simultaneously.  There is not a wave in still water.
exists x1 x2 x3.(a_topic(x1) & over(x1,x3) & n_wave(x3) & n_airborne(x1) & of(x1,x2) & n_surfer(x2))
exists e1 s1 x1 x2.(in(e1,x2) & n_water(x2) & a_still(s1) & Theme(s1,x2) & Actor(e1,x1) & v_swim(e1) & n_person(x1))