Two people stand before an ambulance.
Two people are crossing the street in front of an ambulance.
two people standing before an ambulance does not imply they are crossing street in front of an ambulance
exists e1 x1 x2.(before(e1,x2) & n_ambulance(x2) & Actor(e1,x1) & v_stand(e1) & n_people(x1) & card_eq_2(x1))
exists e1 x1 x2 x3 x4.(n_street(x2) & in(e1,x3) & of(x3,x4) & n_ambulance(x4) & n_front(x3) & Theme(e1,x2) & Actor(e1,x1) & v_cross(e1) & n_people(x1) & card_eq_2(x1))