Three people jumping on a lake.
Three people are jumping at the lake outside.
The fact that the people are jumping doesn't necessarily imply they are outside.
exists e1 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_lake(x3) & Actor(e1,x2) & v_jump(e1) & (x1 = x2) & n_people(x1) & card_eq_3(x1))
exists e1 x1 x2 x3.(n_outside(x2) & of(x2,x3) & n_lake(x3) & at(e1,x2) & Actor(e1,x1) & v_jump(e1) & n_people(x1) & card_eq_3(x1))