A cowboy on the back of a galloping horse.
A cowboy is on the horse while people are watching.
Not all cowboy on the back of a galloping horse have people watching him.
exists x1 x2 x3 x4.(n_back(x2) & a_topic(x1) & on(x1,x2) & of(x2,x3) & n_horse(x3) & of(x3,x4) & n_galloping(x4) & n_cowboy(x1))
exists p1 p2 x1 x2.(n_horse(x2) & exists e1 x3.(Actor(e1,x3) & v_watch(e1) & n_people(x3)) & while(p1,p2) & on(x1,x2) & n_cowboy(x1))