People standing in mud.
Some people are on a muddy road.
Not all mud is on a road.
exists e1 x1 x2 x3.(a_topic(x1) & in(e1,x3) & n_mud(x3) & Actor(e1,x2) & v_stand(e1) & (x1 = x2) & n_people(x1))
exists p1 x1.(exists s1 x2.(on(x1,x2) & n_road(x2) & a_muddy(s1) & Theme(s1,x2)) & n_people(x1))