Réponse : Bonjour je t'ai corrigé ton exercice d'anglais en espérant t'avoir aidé ^^
Explications :
1) Heritage Day didn't exist before 1995. → Did l'auxilliaire et exist le verbe
2) South Africa didn't have a day to celebrate its cultural diversity before 1995. → Did l'auxiliaire et have le verbe
3) Robben Island wasn't a museum in the 20th century. → Verbe to be au prétérit
