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A formal letter is a special type of writing that follows a certain format and structure. It is usually addressed to some [authorities|friends], [colleagues|family] or dignitaries.

Formal letters are characterized by the [formal|informal] style of writing:

1. [Formal|Informal] vocabulary and
   [set|metaphorical] phrases: I am writing to apologise, I would rather suggest, etc.
2. The use of [full|contracted] forms: I have always thought about, I am convinced that, etc.
3. [Formal|Informal] greetings and endings: Yours sincerely, To whom it may concern, etc.
4. The use of the [active|passive] voice: I was pleased to get your letter, I can be contacted, etc.
5. [Formal|Informal] linkers: therefore, nevertheless, however, etc.