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".

Copper rods bend easily.
acceptable

I know which guys you've dated, but I don't know which guys you haven't.
acceptable

He kept company some girls who had been injured in the wreck.

unacceptable