To write questions in the passive voice where the words in bold are the answers, you need to focus on the structure of passive sentences. The passive voice typically emphasizes the action and the recipient of the action rather than the subject performing the action. Here is how you can transform the given sentences:
3) Simon is going to organise the party.
Who is the party going to be organised by?
4) A bee stung him.
What was he stung by?
5) Fiona cooked this delicious turkey.
Who was this delicious turkey cooked by?
6) An international company publishes these books.
Who are these books published by?
7) A bomb killed the soldier.
What was the soldier killed by?
In each case, the structure of the question in the passive voice typically starts with the question word (who, what), followed by the form of "to be," the past participle of the verb, and then "by" to indicate the original subject of the action.