A girl dances with a person dressed as Stitch.
Sally danced with someone.
Just because a girl dances does not mean that girl was Sally.
exists e2 e1 x1 x2 x3 x4.(ne_nam_stitch(x4) & with(e1,x2) & as(e2,x4) & Theme(e2,x3) & v_dress(e2) & (x2 = x3) & n_person(x2) & Actor(e1,x1) & v_dance(e1) & n_girl(x1))
exists s1 x1 x2.(r_sally(s1) & with(s1,x2) & n_person(x2) & Theme(s1,x1) & a_dance(s1) & n_thing(x1))