: Think about the context. Was "bla bla a1" part of an email, a course description, or a book title?
Grammar is simplified. The full PDF will explain: bla bla a1 pdf full
(e.g., Alter Ego+ A1 , Bla Bla Bla coursebook, etc.) — try searching on the publisher's website, educational platforms (like Didier FLE, Hueber, etc.), or legal sources like Amazon Kindle , Google Books , or archive.org for free public domain or sample versions. : Think about the context