A man drives a large truck.
A person operates a vehicle.
A man can be a person and a large truck is a vehicle.
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_drive(e1) & n_truck(x2) & a_large(s1) & Theme(s1,x2) & n_man(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_operate(e1) & n_vehicle(x2) & n_person(x1))