Young girls practicing gymnastics.
The girls are performing on the mats.
Those perfecting gymnastics might not necessarily be performing on the mats.
exists e1 s1 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_practice(e1) & n_gymnastics(x3) & (x1 = x2) & n_girl(x1) & a_young(s1) & Theme(s1,x1))
exists e1 x1 x2.(n_mat(x2) & n_girl(x1) & on(e1,x2) & Actor(e1,x1) & v_perform(e1))