people are walking down an alley.
The people are roller blading.
Walking and roller blading are different.
exists e1 s1 x1 x2.(a_down(s1) & Manner(e1,s1) & Theme(e1,x2) & Actor(e1,x1) & v_walk(e1) & n_alley(x2) & n_people(x1))
exists e1 x1 x2.(n_people(x1) & Time(e1,x2) & n_roller(x2) & Actor(e1,x1) & v_blade(e1))