Diners are sitting at tables in a restaurant.
Diners are at a restaurant.
Diners sitting at tables in a restaurant are at a restaurant.
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 p1 x1.(exists x2.(at(x1,x2) & n_restaurant(x2)) & n_diner(x1))