Four children do backbends in the park.
Some kids are practicing gymnastics.
Children doing backbends are not necessarily practicing gymnastics.
exists e1 x1 x2 x3.(n_park(x3) & in(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_do(e1) & n_backbend(x2) & n_child(x1) & card_eq_4(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_practice(e1) & n_gymnastics(x2) & n_kid(x1))