<https://english2ever.com/%d8%a7%d9%84%d9%85%d8%a7%d8%b6%d9%8a-%d8%a7%d9%84%d8%aa%d8%a7%d9%85-past-perfect/#breadcrumb>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://english2ever.com/%D8%A7%D9%84%D9%85%D8%A7%D8%B6%D9%8A-%D8%A7%D9%84%D8%AA%D8%A7%D9%85-past-perfect/>