Can you please check whether these sentences are grammatically correct?
1. No Admission without permission.
2. Do not enter without permission.
3. Please be careful while you are using the stairs.
4. Switch off the fan and the lights after use.
5. Do not make noise. Thank you.
6. Keep our school clean.
7. Keep the toilet clean.
8. Please turn off the tap after use.
9. Please queue up.
10.Please knock on the door before you enter.