A wooden fence keeps the horse's safe.
the horse's are kept inside around a fence
The presence of a wooden fence does not necessarily imply that horses are kept inside it.
exists e1 s1 x1 x2 x3.(n_safe(x3) & of(x3,x2) & n_horse(x2) & Theme(e1,x3) & Actor(e1,x1) & v_keep(e1) & n_fence(x1) & a_wooden(s1) & Theme(s1,x1))
exists e1 s1 x1 x2 x3.(n_'s(x1) & of(x1,x2) & n_horse(x2) & around(e1,x3) & n_fence(x3) & a_inside(s1) & Manner(e1,s1) & Theme(e1,x1) & v_keep(e1))