what's the meaning of this sentence?

We do not know the official date that he got a job as a teacher. It was sometime in 2008 or 2009.

Clive

Thank you! But why not use "it was in 2008-09" here?

I was trying to clarify the meaning, as you requested.
I thought you might not understand 2008-09.

I understand it. I just wonder that if the meaning is "It was sometime in 2008 or 2009", why didn't the original author write "it was in 2008-09" directly in the sentence. In fact, he write "it would have been in 2008-09"
I want to know what's the difference between them?

Thanks for your help!

"It was sometime in 2008 or 2009", why didn't the original author write "it was in 2008-09" directly in the sentence. In fact, he write "it would have been in 2008-09"
I want to know what's the difference between them?
There's not a lot of difference.


It was sometime in 2008 or 2009

Thanks Clive!

has been become is also correct right?

He has been become? Difinitely wrong!
He has been a teacher for a couple of years.

There is an implied phrase omitted from the parenthetical that makes it grammatical: "(other than it would have been in 2008-2009 that he became a teacher.)". If you assume this, it's fine, although it's a little awkward for formal business writing. I would instead say "We don't know specifically when he became a teacher (but if would have been in 2008-2009)." Same implied omissio