Bonsoir,
a- The room where you are sitting is not well aerated.
Would you mind opening the window to get some fresh air, please ?
b-You do not know the way to the post office.
Could you tell me the way to the post office, please ?
c- A passenger is smoking in your train compartment.
Would you mind not smoking here, please ?
ou
Would you be so kind as to stop smoking ?
d- you could not hear what a person was saying
Could you repeat what you said, please ?
bonne soirée ☺☺☺