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".

A boy did not laugh.
acceptable

Willy is taller than that Bill is is generally believed.
unacceptable

Bake for 30 minutes.

acceptable