I'm trying to understand why there is this "with". I can say "Let's get this done". So, why "Let's get this over with?" I would really appreciate if someone could explain that a bit.
Recently one of my friends who is not a native English speaker sent me a mail. In the last phrase he used a harmonic but strange structure instead of the usual phrases like "Best Regards", "Best ...
What is the grammatical interpretation of the phrase? I don't understand what verb tense or voice is used.