The boys are playing soccer.
People are playing soccer.
Boys are human beings which can the named "people".
exists e1 x1 x2.(n_boy(x1) & Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_soccer(x2))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_play(e1) & n_soccer(x2) & n_people(x1))