Some firefighters check a vehicle.
Firefighters are checking a car.
A vehicle can be a car.
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_check(e1) & n_vehicle(x2) & n_firefighter(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_check(e1) & n_car(x2) & n_firefighter(x1))