People protesting immigration.
People are picketing illegal immigration.
Not all immigration that people protest is illegal.
exists e1 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_protest(e1) & n_immigration(x3) & (x1 = x2) & n_people(x1))
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_picket(e1) & n_immigration(x2) & a_illegal(s1) & Theme(s1,x2) & n_people(x1))