it must be "Johano amas sian fraton kaj sian filon" if it is his own
(John's) son, because John is the subject, but we must say "lian filon"
if the brother's son is meant. "La knaboj alportis al siaj patroj siajn
cxapelojn" means "The boys brought to their fathers their own (the
boys') hats," because "boys" is the subject, but if we mean "the
fathers' hats" it must be "iliajn cxapelojn."

"She gave to her sister her book" must be "Sxi donis al sia fratino sian
libron" if it were her own book, but "Sxi donis al sia fratino sxian
libron" if it were her sister's book. "Li diris al si"... means "He
said to himself," but "Li diris al li" means that he said it to another
person.

"Si", "sia", can only "refer to" the subject, it cannot be the subject
itself or any part of it; therefore we must say "Sinjoro P. kaj lia
edzino tre amas miajn infanojn", because the subject is "Sinjoro P. kaj
lia edzino."

"Mem," self, is only used for emphasis, "e.g.", "Mi mem," my (own) self.

VOCABULARY.

gasto : guest. montr- : show.
vespero : evening. fleg- : tend, take care of
mangxo : meal. re-ven- : come back.
pupo : doll. pri : concerning, about.
aventuro : adventure. gxis : until, as far as.
palaco : palace. tute : quite, wholly.
zorg- : take care of. tute ne : not at all.
gard- : guard. kun : with.