A red car is passing in front of a double-decker bus.
There are no red cars in front of a bus
If there are no red cars a red car is not passing.
exists e1 s1 s2 x1 x2 x3.(in(e1,x2) & of(x2,x3) & n_bus(x3) & a_double-decker(s2) & Theme(s2,x3) & n_front(x2) & Actor(e1,x1) & v_pass(e1) & n_car(x1) & a_red(s1) & Theme(s1,x1))
exists p1 x1 x2 x3.(in(p1,x2) & of(x2,x3) & n_bus(x3) & n_front(x2) & -exists s1 x4.((x1 = x4) & n_car(x4) & a_red(s1) & Theme(s1,x4)))