A BMX rider on the trail.
A person is running a marathon.
Being a BMX rider implies he is riding a bike and cannot be running.
exists x1 x2 x3.(n_trail(x3) & a_topic(x1) & on(x1,x3) & n_rider(x1) & (x1 = x2) & ne_org_bmx(x2))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_run(e1) & n_marathon(x2) & n_person(x1))