One girl is playing a recorder and another girl is playing the guitar.
they are in a class
Playing a recorder and playing the guitar does not imply being in a class.
exists e2 e1 x1 x2 x3 x4.(n_guitar(x4) & Theme(e2,x4) & Actor(e2,x3) & v_play(e2) & n_girl(x3) & -(x3 = x1) & n_girl(x1) & n_girl(x1) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_recorder(x2) & card_eq_1(x1))
exists p1 x1.(n_thing(x1) & exists x2.(in(x1,x2) & n_class(x2)))