a boy runs through the grass.
A boy crawls through the mud.
Runs is not crawls
exists e1 x1 x2.(n_grass(x2) & through(e1,x2) & Actor(e1,x1) & v_run(e1) & n_boy(x1))
exists e1 x1 x2.(n_mud(x2) & through(e1,x2) & Actor(e1,x1) & v_crawl(e1) & n_boy(x1))