A boy in yellow walks down the street.
The boy is walking.
Walking is a rephrasing for walks.
exists e1 x1 x2 x3.(n_street(x3) & down(e1,x3) & Actor(e1,x1) & v_walk(e1) & in(x1,x2) & n_yellow(x2) & n_boy(x1))
exists e1 x1.(n_boy(x1) & Actor(e1,x1) & v_walk(e1))