People attending an event in a park.
There is an event at the park.
In order for people to attend an event in a park there has to be an event at the park.
exists e1 x1 x2 x3 x4.(a_topic(x1) & Theme(e1,x3) & Actor(e1,x2) & v_attend(e1) & in(x3,x4) & n_park(x4) & n_event(x3) & (x1 = x2) & n_people(x1))
exists p1 x1 x2.(n_park(x2) & at(p1,x2) & exists x3.((x1 = x3) & n_event(x3)))