Answer:
2. The computer is being used.
3. The conversation was recorded without being noticed.
4. The game was canceled shortly after arriving at the stage.
5. A new ring road is being built around the city.
6. A hospital is being built near the airport.
Explanation:
As requested in the question above, all phrases have been rewritten to present a passive voice in place of the active voice.
Passive voice phrases are those that do not present the subject as the provider of the verb, that is, the verb does not suffer the action of the subject that is not presented as the element that performs the action.