People crossing a busy street.
People are crossing the street.
"People crossing street" is another way of saying People are crossing the street.
exists e1 s1 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_cross(e1) & n_street(x3) & a_busy(s1) & Theme(s1,x3) & (x1 = x2) & n_people(x1))
exists e1 x1 x2.(n_street(x2) & Theme(e1,x2) & Actor(e1,x1) & v_cross(e1) & n_people(x1))