Band members are playing a song on stage.
band members on stage singing on wedding
The band members aren't necessarily singing or  at a wedding.
exists e1 x1 x2 x3 x4.(on(e1,x4) & n_stage(x4) & Theme(e1,x3) & Actor(e1,x1) & v_play(e1) & n_song(x3) & n_member(x1) & (x1 = x2) & ne_nam_band(x2))
exists e1 x1 x2 x3 x4 x5.(a_topic(x1) & on(e1,x5) & n_wedding(x5) & Actor(e1,x4) & v_sing(e1) & (x1 = x4) & on(x1,x3) & n_stage(x3) & n_member(x1) & of(x1,x2) & n_band(x2))