The letter was buried under the papers.
He confessed the letter (to be) a forgery.
I sent an acknowledgment of his letter.
He wrote the letter with a fountain pen.
He knew that the letter was written in ink.
He folded the letter and put it in an envelope.
Having written the letter, he went out.
He went to the post office to mail the letter.
He attached a stamp (to the letter).
Our letters crossed.
He balled up the letter and tossed it away.