A group of people are watching the trains at a train stop.
people are visiting santa claus in the north pole while riding reindeer
If people are watching the trains, they would not be riding reindeer and visiting santa.
exists e1 x1 x2 x3 x4.(at(e1,x4) & n_stop(x4) & of(x4,x3) & n_train(x3) & n_train(x3) & Theme(e1,x3) & Actor(e1,x1) & v_watch(e1) & of(x1,x2) & n_people(x2) & n_group(x1))
exists e1 e2 x1 x2 x3 x4 x5 x6.(n_pole(x4) & of(x4,x5) & n_north(x5) & while(e1,e2) & Theme(e2,x6) & Actor(e2,x1) & v_ride(e2) & n_reindeer(x6) & in(e1,x4) & Theme(e1,x2) & Actor(e1,x1) & v_visit(e1) & n_claus(x2) & of(x2,x3) & n_santa(x3) & n_people(x1))