Questions & Answers about Θα δουλεύω στο γραφείο μέχρι να φτάσεις.
Modern Greek has two basic future aspects:
Θα δουλεύω = future continuous (using the present stem)
– ongoing / repeated action in the future
– corresponds to “I will be working / I’ll be working”Θα δουλέψω = future simple (using the aorist stem)
– one‑off, completed action in the future
– corresponds roughly to “I will work / I’ll get some work done”
In Θα δουλεύω στο γραφείο μέχρι να φτάσεις, the idea is that the working is an ongoing activity that lasts up to the moment you arrive. That matches the continuous aspect: Θα δουλεύω.
You could say Θα δουλέψω στο γραφείο μέχρι να φτάσεις, but that sounds more like “I’ll do some work at the office until you arrive” (emphasis on the fact of doing some work, not on the ongoing activity). The original sentence sounds more natural for “I will be working at the office until you arrive.”