A dog runs across the grass.
A dog is running.
It is the same sentence in a different tense. Dog runs verse, Dog is running
exists e1 x1 x2.(n_grass(x2) & across(e1,x2) & Actor(e1,x1) & v_run(e1) & n_dog(x1))
exists e1 x1.(Actor(e1,x1) & v_run(e1) & n_dog(x1))