Την Πέμπτη ο καθηγητής μας λέει τους βαθμούς από την εξέταση.

from

Breakdown of Την Πέμπτη ο καθηγητής μας λέει τους βαθμούς από την εξέταση.

• μας: our
• λέω: to tell
• ο καθηγητής: the male professor

Questions & Answers about Την Πέμπτη ο καθηγητής μας λέει τους βαθμούς από την εξέταση.

Why is it Την Πέμπτη and not Η Πέμπτη? What does the accusative here mean?

With days of the week, Greek often uses the accusative with the definite article to mean “on [that day]”.

• Την Πέμπτη = on Thursday (this coming or a specific Thursday)
• Η Πέμπτη = Thursday as a subject or topic (e.g. Η Πέμπτη είναι δύσκολη μέρα – Thursday is a difficult day).

So Την Πέμπτη is an accusative of time: it answers the question πότε; (when?), meaning “On Thursday…”

Why is the word order Την Πέμπτη ο καθηγητής μας λέει… and not Ο καθηγητής μας λέει… την Πέμπτη? Is there a difference?

Both are grammatically correct; Greek word order is relatively flexible.

• Την Πέμπτη ο καθηγητής μας λέει τους βαθμούς…
  Puts a bit more emphasis on the time: As for Thursday – that’s when our teacher tells the grades…

• Ο καθηγητής μας λέει τους βαθμούς την Πέμπτη.
  More neutral; starts with “our teacher” as the topic.

In many contexts they mean the same; the choice is mainly about rhythm and which element you want to highlight.

What exactly does ο καθηγητής μας mean? Is μας “us” as an object?