The people are marching through the street.
People are marching on a field.
The people are either in the field or the street.
exists e1 x1 x2.(n_street(x2) & n_people(x1) & through(e1,x2) & Actor(e1,x1) & v_march(e1))
exists e1 x1 x2.(on(e1,x2) & n_field(x2) & Actor(e1,x1) & v_march(e1) & n_people(x1))