A dog runs through the grass.
A dog running through the grass
To be running is to runs.
exists e1 x1 x2.(n_grass(x2) & through(e1,x2) & Actor(e1,x1) & v_run(e1) & n_dog(x1))
exists e1 x1 x2 x3.(n_grass(x3) & a_topic(x1) & through(e1,x3) & Actor(e1,x2) & v_run(e1) & (x1 = x2) & n_dog(x1))