A group of people playing instruments.
A band is practicing for their show
The people playing their instruments may actually not be a band that's practicing for a show.
exists e1 x1 x2 x3 x4.(a_topic(x1) & of(x1,x2) & Theme(e1,x4) & Actor(e1,x3) & v_play(e1) & n_instrument(x4) & (x2 = x3) & n_people(x2) & n_group(x1))
exists e1 x1 x2.(for(e1,x2) & n_show(x2) & of(x2,x1) & n_thing(x1) & Actor(e1,x1) & v_practice(e1) & n_band(x1))