A man surfing.
A man is surfing big waves.
A man is not always surfing big waves.
exists x1 x2.(a_topic(x1) & n_surfing(x1) & of(x1,x2) & n_man(x2))
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_surf(e1) & n_wave(x2) & a_big(s1) & Theme(s1,x2) & n_man(x1))