A child bangs on a set of drums.
The child is playing the drums.
One who bangs on a set of drums is playing the drums.
exists x1 x2 x3 x4.(a_topic(x1) & on(x1,x3) & of(x3,x4) & n_drum(x4) & n_set(x3) & n_bang(x1) & of(x1,x2) & n_child(x2))
exists e1 x1 x2.(n_drum(x2) & n_child(x1) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1))