Построить общий вопрос и еще несколько к данному предложению: the letter has just been typed.

Has the letter just been typed?
What has just been typed?
The letter has just been typed, hasn't it?
The letter has just been typed or written?

Дополнительно можно:
By whom the letter has just been typed?
Where the letter has just been typed?

Has the letter been typed yet?
what has just been typed?
has the letter or the report been typed?
the letter has just been typed,hasn't it?