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".

Q: Have in our class the kids arrived safely?

A: unacceptable
****
Q: The men would all not have been working.

A: unacceptable
****
Q: I am not certain about if he will come.

A:
unacceptable
****