Here's why:
* Subject: The subject of a sentence is the noun or pronoun that performs the action of the verb.
* Prepositional Phrase: A prepositional phrase is a group of words that begins with a preposition (like "in," "on," "to," "with," "for") and ends with a noun or pronoun (the object of the preposition).
Prepositional phrases modify other words in the sentence, but they don't change the subject.
Example:
* The cat in the hat is sleeping.
* Subject: The cat
* Prepositional Phrase: in the hat
The prepositional phrase "in the hat" tells us where the cat is sleeping, but it doesn't change the fact that the cat is the one doing the sleeping.