In French, when we use the helping verb être, past participles change to match the subject. But when we use avoir, they usually don’t change unless there is a direct object before the verb.

Using Être:

• Example: Elle est partie (She left).
  • In this case, partie matches "elle."

Using Avoir:

• Example: Il a mangé les pommes (He ate the apples).

  • Here, there’s no matching because "les pommes" comes after the verb.

• If the direct object is before the verb:

  • Example: Les pommes, il les a mangées (The apples, he ate them).
  • In this sentence, mangées matches "les pommes."

Just remember this rule, and you’ll get the hang of past participle agreements really quickly!