A gray bird is flying through the trees.
There is a bird flying past an oak tree.
There nay be an oak tree or a maple tree.
exists e1 s1 x1 x2.(n_tree(x2) & through(e1,x2) & Actor(e1,x1) & v_fly(e1) & n_bird(x1) & a_gray(s1) & Theme(s1,x1))
exists p1 x1 e1 x2 x3 x4 x5.((x1 = x2) & past(e1,x4) & n_tree(x4) & of(x4,x5) & n_oak(x5) & Actor(e1,x3) & v_fly(e1) & (x2 = x3) & n_bird(x2))