A man in a gray vehicle feeding sheep.
The man is riding a horse.
The man can't be riding a gray vehicle and riding a horse simultaneously.
exists s1 x1 x2 x3 x4.(a_topic(x1) & in(x1,x2) & n_sheep(x2) & of(x2,x4) & n_feeding(x4) & of(x2,x3) & n_vehicle(x3) & a_gray(s1) & Theme(s1,x2) & n_man(x1))
exists e1 x1 x2.(n_man(x1) & Theme(e1,x2) & Actor(e1,x1) & v_ride(e1) & n_horse(x2))