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".

Not many books survived the fire, did they?
acceptable

Sam may have been being interrogated by the FBI.
acceptable

Willy is taller than Bill by as much as Joe is taller than the Dan.

acceptable