A trio of singers, each with a microphone; two are playing guitar and keyboard.
Singers are practicing for concert.
Just because they are playing does not mean they are practicing for a concert.
exists e1 x1 x2 x3 x4 x5 x6 x7.(Theme(e1,x5) & Actor(e1,x1) & v_play(e1) & n_keyboard(x7) & n_guitar(x6) & subset_of(x7,x5) & subset_of(x6,x5) & of(x1,x2) & rel(x2,x3) & subset_of(x4,x3) & n_thing(x4) & card_eq_2(x4) & all x8.(n_thing(x8) -> exists x9.(subset_of(x8,x3) & with(x8,x9) & n_microphone(x9))) & n_singer(x2) & n_trio(x1))
exists e1 x1 x2.(for(e1,x2) & n_concert(x2) & Actor(e1,x1) & v_practice(e1) & n_singer(x1))