You recently went on a trip with your friend and you both took some photographs.
Write a letter to your friend. In your letter
Ask your friend to send you one of the photographs. Explain why you need that particular photograph. And tell your friend what happened to your copy of it.
You are experiencing financial problems and want to ask your landlord if you can pay your rent late. Write a letter to your landlord.
In your letter explain:
Why you are writing to him.
Why you cannot pay the rent.
When you will pay the rent.