A girl rides a horse.
A girl saddles a horse.
A girl couldn't rides a horse if she never saddles it.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_horse(x2) & n_girl(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_saddle(e1) & n_horse(x2) & n_girl(x1))