Here's why:
* Passive voice is a grammatical construction where the subject of a sentence is acted upon, rather than acting. This is achieved by using a form of the verb "to be" followed by the past participle of the main verb.
* Nouns are words that name people, places, things, or ideas. They are the subjects or objects of verbs, but they don't change their form to indicate passive voice.
Example:
* Active voice: The dog chased the ball. (The dog is the subject, acting upon the ball)
* Passive voice: The ball was chased by the dog. (The ball is the subject, acted upon by the dog)
In both cases, "ball" remains a noun. It's the verb ("chased" and "was chased") that changes form to indicate passive voice.
Key Takeaway: Nouns don't have passive cases. The passive voice is a feature of verbs.