A seagull lands on the water.
A bird in a tree.
The seagull can not be in a tree if it is on water
exists s1 x1 x2.(n_water(x2) & a_topic(x1) & on(x1,x2) & n_land(x1) & a_seagull(s1) & Theme(s1,x1))
exists x1 x2.(a_topic(x1) & in(x1,x2) & n_tree(x2) & n_bird(x1))