There are several trees around the horses.
The horses observe the trees
Sentence 1 is missing horses observe the trees
exists p1 x1 x3.(n_horse(x3) & exists s1 x2.((x1 = x2) & around(x2,x3) & n_tree(x2) & a_several(s1) & Theme(s1,x2)))
exists e1 x1 x2.(n_tree(x2) & n_horse(x1) & Theme(e1,x2) & Actor(e1,x1) & v_observe(e1))