Two armed police officers are patrolling the streets.
There are police officers on the streets.
Saying police are on the streets is another way of saying they are patrolling them.
exists e1 s1 x1 x2 x3.(n_street(x3) & Theme(e1,x3) & Actor(e1,x1) & v_patrol(e1) & n_officer(x1) & of(x1,x2) & n_police(x2) & a_armed(s1) & Theme(s1,x1) & card_eq_2(x1))
exists p1 x1 x4.(n_street(x4) & exists x2 x3.((x1 = x2) & on(x2,x4) & n_officer(x2) & of(x2,x3) & n_police(x3)))