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".

What do you think he is doing now?
acceptable

I admired his honesty.
acceptable

Any pilot on duty today must be flying this plane.

unacceptable