A man in black surfs on a wave.
The guy is surfing.
A guy is a man.  Surfing is a conjugation of surfs.
exists s1 x1 x2 x3.(a_topic(x1) & in(x1,x2) & on(x2,x3) & n_wave(x3) & n_surf(x2) & a_black(s1) & Theme(s1,x2) & n_man(x1))
exists e1 x1.(n_guy(x1) & Actor(e1,x1) & v_surf(e1))