a boy walks through the lawn.
A boy walking in the grass.
A boy is walking through the grass
exists e1 x1 x2.(n_lawn(x2) & through(e1,x2) & Actor(e1,x1) & v_walk(e1) & n_boy(x1))
exists x1 x2 x3.(n_grass(x3) & a_topic(x1) & in(x1,x3) & n_walking(x1) & of(x1,x2) & n_boy(x2))