Hundreds of people gathered at an event.
People are watching a concert.
People gathered doesn't mean they are watching and event isn't always a concert.
exists e1 x1 x2 x3.(at(e1,x3) & n_event(x3) & Actor(e1,x1) & v_gather(e1) & of(x1,x2) & n_people(x2) & n_hundred(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_watch(e1) & n_concert(x2) & n_people(x1))