A couple walks down the sidewalk.
A couple is walking.
Walking down the side walk is walking.
exists e1 s1 x1 x2.(n_sidewalk(x2) & a_down(s1) & Manner(e1,s1) & Theme(e1,x2) & Actor(e1,x1) & v_walk(e1) & n_couple(x1))
exists e1 x1.(Actor(e1,x1) & v_walk(e1) & n_couple(x1))