There is a truck on fire.
A vehicle in a mishap.
Vehicles usually get on fire after a mishap.
exists p1 x1 x2 x3.((x1 = x2) & on(x2,x3) & n_fire(x3) & n_truck(x2))
exists x1 x2.(a_topic(x1) & in(x1,x2) & n_mishap(x2) & n_vehicle(x1))