A man is standing by trees.
A man is climbing the tree.
He cannot be standing by the tree and climbing the tree at the same time.
exists e1 x1 x2.(by(e1,x2) & n_tree(x2) & Actor(e1,x1) & v_stand(e1) & n_man(x1))
exists e1 x1 x2.(n_tree(x2) & Theme(e1,x2) & Actor(e1,x1) & v_climb(e1) & n_man(x1))