je dois faire un exposé sur mes vacances mes je ne sais pas quoi ecrire.

Tu pourrais par exemple écrire :

During my holidays, I went to (écrire Le nom d'un pays) with my family.
On the first evening of this holidays, I ate in a restaurant, and after that, I went to the cinema with my (brother/sister).
On the first week, I did some horse riding, and I invited my friends to my party.
On the second week, I did my homework, and I stayed at home, to rest a little before return to school.

En espérant t'avoir aidé ! Bonne Chance !