Three people on stage singing and playing instruments.
A band practicing their dance moves.
The subjects cannot be singing and playing instruments on stage and thus performing,  as well as practicing dance moves.
exists x1 x2 x3 x4 x5.(a_topic(x1) & on(x1,x2) & n_instrument(x2) & of(x2,x5) & n_playing(x5) & of(x2,x4) & n_singing(x4) & of(x2,x3) & n_stage(x3) & n_people(x1) & card_eq_3(x1))
exists e1 x1 x2 x3 x4.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_practice(e1) & n_move(x3) & of(x3,x4) & n_dance(x4) & of(x3,x1) & n_thing(x1) & (x1 = x2) & n_band(x1))