_a._ Of the introduction. Write out the introduction
in detail, both name and address. Abbreviating this
part of the letter is highly discourteous.
_b._ In the body of the letter; as,
_Wrong_: The Co. sent a no. of large orders last year.
_c._ Of the courteous close; as,
_Wrong_: Yours etc.
_Wrong_: Yours resp'y.