A surfer is riding a very big wave.
The surfer is on the beach under an umbrella.
One can't ride a very big wave and be on the beach at the same time.
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_wave(x2) & a_big(s1) & Theme(s1,x2) & r_very(x2) & n_surfer(x1))
exists p1 x1 x2 x3.(n_beach(x3) & n_surfer(x1) & under(p1,x2) & n_umbrella(x2) & on(x1,x3))