Hundreds of people gathered at an event.
The event that people gathered was a concert
There are other events besides 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 p1 p2 x1.(Topic(x1,p1) & exists e1 x2.(Actor(e1,x2) & v_gather(e1) & n_people(x2)) & n_event(x1) & exists x3.((x1 = x3) & n_concert(x3)))