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".
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Question: I threw Mary the ball, but she was looking at the birds flying overhead and didn't even notice.

Answer: acceptable


Question: The problem knows easily.

Answer: unacceptable


Question: They believe that Charles Darwin's theory of evolution is just a scientific theory.

Answer:
acceptable