A man is sitting in the grass behind a tree.
A man sits outside.
In the grass behind a tree are descriptive of outside.
exists e1 x1 x2 x3.(n_grass(x2) & behind(e1,x3) & n_tree(x3) & in(e1,x2) & Actor(e1,x1) & v_sit(e1) & n_man(x1))
exists e1 p1 x1.(exists s1.(Theme(s1,x1) & a_outside(s1)) & Topic(e1,p1) & Actor(e1,x1) & v_sit(e1) & n_man(x1))