A cop stands in front of a car on a busy street.
A clown stand on top of a car on a deserted street.
A cop and a clown are different types of people.  One cannot be on top of a car and in front of a car simultaneously.  A busy street is not deserted.
exists e1 s1 x1 x2 x3 x4.(in(e1,x2) & on(x2,x4) & n_street(x4) & a_busy(s1) & Theme(s1,x4) & of(x2,x3) & n_car(x3) & n_front(x2) & Actor(e1,x1) & v_stand(e1) & n_cop(x1))
exists s1 s2 x1 x2 x3 x4.(a_topic(x1) & on(x1,x2) & of(x2,x3) & on(x3,x4) & n_street(x4) & a_deserted(s2) & Theme(s2,x4) & n_car(x3) & n_top(x2) & n_stand(x1) & a_clown(s1) & Theme(s1,x1))