A young boy is walking in a grassy field.
a boy is running at full speed
The boy cannot be walking and running at the same time.
exists e1 s1 s2 x1 x2.(in(e1,x2) & n_field(x2) & a_grassy(s2) & Theme(s2,x2) & Actor(e1,x1) & v_walk(e1) & n_boy(x1) & a_young(s1) & Theme(s1,x1))
exists e1 s1 x1 x2.(at(e1,x2) & n_speed(x2) & a_full(s1) & Theme(s1,x2) & Actor(e1,x1) & v_run(e1) & n_boy(x1))