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".

Fluffy is sick, which nobody knows.
acceptable

Penny rowed across the lake.
acceptable

The students looked the high stairs up from the floor.

unacceptable