You're given a sentence and your task is to classify whether the sentence is acceptable or not. Any sentence which is grammatically correct, has a naturalistic text, is written by a native speaker and which minimizes superfluous content is acceptable, otherwise unacceptable. If the sentence is acceptable then write "acceptable", otherwise "unacceptable".

Nora sent at the book to Peter.
unacceptable

One of the problems was the robins.
acceptable

It proves that John is the murderer that he has blood on his hands.

unacceptable