* Subjects are usually nouns or pronouns: The subject of a sentence is the person, place, thing, or idea that performs the action of the verb. For example:
* The cat chased the mouse. ("Cat" is the subject)
* He ran to the store. ("He" is the subject)
* Prepositional phrases function differently: Prepositional phrases begin with a preposition (like "on," "in," "with," "to," etc.) and usually modify a noun or verb. They don't typically function as subjects. For example:
* The cat chased the mouse in the kitchen. ("In the kitchen" is a prepositional phrase modifying "chased")
* He ran to the store ("To the store" is a prepositional phrase modifying "ran")
However, there are some instances where a prepositional phrase *can* act as the subject:
* When the prepositional phrase includes a noun that functions as the subject:
* Under the bed is where I found the lost earring. (The noun "bed" within the phrase functions as the subject)
* After the game was a time for celebration. (The noun "game" within the phrase functions as the subject)
In summary: While subjects are usually nouns or pronouns, sometimes a prepositional phrase can contain a noun that functions as the subject of the sentence.