Little girl wearing a colorful hat while propped up on a cushion.
A girl rides a horse in a field.
A girl does not have to be little.  If a girl is propped up on a cushion she can not rides a horse.
(x)
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & in(x2,x3) & n_field(x3) & n_horse(x2) & n_girl(x1))