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".

John's refusing the offer is shocking.
acceptable

He never achieved anything, didn't he?
unacceptable

The tank filled with petrol out of the pump.

acceptable