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".

Which packages didn't Sam pick up which are to be mailed tomorrow until it had stopped raining?
unacceptable

Stephen believed the cat to be out of the bag.
acceptable

Ten pounds was weighed by the package.

unacceptable