A group of people are having a picnic at the park.
A group of people celebrate with a picnic in the park.
Just because people are having a picnic it does not mean they celebrate.
exists e1 x1 x2 x3 x4.(n_park(x4) & at(e1,x4) & Theme(e1,x3) & Actor(e1,x1) & v_have(e1) & n_picnic(x3) & of(x1,x2) & n_people(x2) & n_group(x1))
exists e1 x1 x2 x3 x4.(n_park(x4) & with(e1,x3) & in(x3,x4) & n_picnic(x3) & Actor(e1,x1) & v_celebrate(e1) & of(x1,x2) & n_people(x2) & n_group(x1))