Can I say "Εγώ ξέρω αυτό το μέρος"?
Yes, of course you can. ;) Was it not accepted?
Ι said the same as Anas a year ago and it was rejected
μπρορώ να χρησιμοποιήσω επίσης; ξέρω αυτή τη πλατεία
If you mean in the sentence above, you can't because πλατεία=town square, plaza. Otherwise it's: Ξέρω αυτήν την πλατεία=i know this square.
Does the word μέρος mean both place and part?
I remember it being used as part in the Parts of Speech skill.
If so, could you translate this sentence as: 'I know this part.'