Firefighters stand on moist ground with a firetruck.
There was a fire.
Firefighters standing does not necessarily imply there was a fire.
exists e1 x1 x2 x3 x4.(on(e1,x2) & with(x2,x4) & n_firetruck(x4) & n_ground(x2) & of(x2,x3) & n_moist(x3) & Actor(e1,x1) & v_stand(e1) & n_firefighter(x1))
exists p1 x1 x2.((x1 = x2) & n_fire(x2))