Questions & Answers about Patron bir e-posta gönderdi mi?
Why is the question particle mi used here instead of mı or mu?
Even though the question particle is written as a separate word, it still follows the rules of 4-way vowel harmony with the word right before it. Since the last vowel in gönderdi is i, the particle becomes mi.
What part of gönderdi shows that this happened in the past?
The -di suffix is the past tense marker attached to the verb root gönder- (to send). Because the subject is third-person singular ("the boss"), there are no extra personal endings added after -di.
Could I put mi after Patron instead?
Yes, but it would change the focus of the question! In Turkish, you put the question particle right after the word you want to ask about. Putting it at the end asks a general yes/no question about the action. If you said Patron mu bir e-posta gönderdi?, you would specifically be asking "Was it the boss who sent an email?" (Notice it becomes mu to match the 'o' in Patron).
Why does bir come before e-posta instead of after?
In Turkish, bir acts as the indefinite article "a" or "an". Just like in English, it always comes right before the noun it describes. So, "an email" is translated in that exact order: bir e-posta.