Prośby
Please could you give me a ring on Thursday / Would you be so good / kind as to telephone me on Thursday?
I would be grateful if you could send me a sample.
I would be grateful for / I would appreciate your help in this matter.
Would you please confirm this in writing? / Would you mind confirming this in writing?
Could you possibly / Would it be possible for you to organize the reception for us?
I must ask you to let us have / [fml] Kindly let us have your payment by return of post.

O informację
Please could you tell me / let me know the prices / send me details of your range of electric cookers.
I don't wish to seem inquisitive, but I'd love to know where you bought that dress.
I would be very grateful for any information you can give me on the availability of spare parts.
[fml] Do not forget to inform us of your new address.
Let us know your new address.

O wyjaśnienie
Please could you give the reason for your departure / explain the reason for your departure / why you have left.
I would be grateful if you could clarify the second paragraph in your letter.
May I ask you why you no longer want the goods?

[fml] - formalnie