Kids sit on a ledge and talk.
Kids are on vacation.
Kids sitting on a ledge and talking are not necessarily on vacation.
exists e1 x1 x2 x3 x4.(on(e1,x2) & n_talk(x4) & n_ledge(x3) & subset_of(x4,x2) & subset_of(x3,x2) & Actor(e1,x1) & v_sit(e1) & n_kid(x1))
exists p1 x1.(exists x2.(on(x1,x2) & n_vacation(x2)) & n_kid(x1))