Here's why:
* Prepositional phrases function as adjectives or adverbs, modifying other parts of the sentence.
* Verbs indicate action or a state of being, which is the core of a sentence's meaning.
Think of it this way: a prepositional phrase describes *where*, *when*, *how*, or *why* something happens, but it doesn't tell you *what* happens. That's the job of the verb.
Example:
* Incorrect: "The dog ran under the table barking loudly." (Barking is a verb, not part of the prepositional phrase)
* Correct: "The dog ran under the table barking loudly."
Let me know if you have any other questions!