A gymnast stretches on the mat.
A girl practising her moves on bar.
If she was doing stretches then she would not be practising her moves.
exists e1 x1 x2.(n_mat(x2) & on(e1,x2) & Actor(e1,x1) & v_stretch(e1) & n_gymnast(x1))
exists e1 x1 x2 x3 x4.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_practise(e1) & on(x3,x4) & n_bar(x4) & n_move(x3) & of(x3,x1) & n_female(x1) & (x1 = x2) & n_girl(x1))