Les vérités qui ont été _dites_, _The truths that have been said._
Les femmes sont _parties_, _The women have left._
L'affaire a été _réglée_, _The business has been settled._
3. When, however, the verb is an accidental reflective originating from
a transitive, then the Participle Past agrees with its direct object
only when preceded by it; when followed after, it is invariable.
Quelles dures vérités ils se sont _dites_,
_What hard truths they have told each other!_
Ils se sont _dit_ de dures vérités,
_They have told each other some hard truths._
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4. When it is derived from an intransitive verb, the Participle Past is
always invariable.
Ils _or_ elles se sont _plu_, _They have pleased each other._
Ils _or_ elles se sont _nui_, _They have injured each other._