Diners are sitting at tables in a restaurant.
Diners are eating lobster.
the diners may or may not be eating lobster
exists e1 x1 x2 x3.(in(e1,x3) & n_restaurant(x3) & at(e1,x2) & n_table(x2) & Actor(e1,x1) & v_sit(e1) & n_diner(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_eat(e1) & n_lobster(x2) & n_diner(x1))