People walking across a footbridge over a lake.
People crossing a lake.
People walking across and crossing a lake are stating the same thing.
exists e1 x1 x2 x3 x4.(a_topic(x1) & over(e1,x4) & n_lake(x4) & across(e1,x3) & n_footbridge(x3) & Actor(e1,x2) & v_walk(e1) & (x1 = x2) & n_people(x1))
exists e1 x1 x2 x3.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_cross(e1) & n_lake(x3) & (x1 = x2) & n_people(x1))