"They ask us about our parents."
Translation:Ili demandas al ni pri niaj gepatroj.
Adding -n makes the word a direct object clarifying who is being asked.
My own question is why the word order can't be switched around and have it be correct still? I thought the order was less important in Esperanto. I put "Ili nin demandas pri niaj gepatroj." And it was wrong wanting nin to be moved after the demandas.