A band is on stage with their instruments.
The all girl band is playing on stage.
Not all bands are all girl bands.  Although they are on stage with their instruments, it does not imply they are playing on stage.
exists p1 x1 x3.(exists x2.(on(x1,x2) & with(x2,x3) & n_stage(x2)) & n_instrument(x3) & of(x3,x1) & n_thing(x1) & n_band(x1))
exists e1 x1 x2 x3.(n_band(x1) & of(x1,x2) & n_girl(x2) & on(e1,x3) & n_stage(x3) & Actor(e1,x1) & v_play(e1))