These people are walking on cement blocks.
These people are walking.
Walking is same as are walking.
exists e1 x1 x2 x3.(n_people(x1) & on(e1,x2) & n_block(x2) & of(x2,x3) & n_cement(x3) & Actor(e1,x1) & v_walk(e1))
exists e1 x1.(n_people(x1) & Actor(e1,x1) & v_walk(e1))