Does a prepositional phrase have to end in noun?

No, a prepositional phrase doesn't *have* to end in a noun. It can end in a pronoun, a gerund (a verb acting as a noun), or even another phrase.

Here are some examples:

* Noun: "The book on the table is mine." (The prepositional phrase ends with "table," a noun)

* Pronoun: "I went to the store with her." (The prepositional phrase ends with "her," a pronoun)

* Gerund: "I am interested in learning new things." (The prepositional phrase ends with "learning new things," a gerund)

* Another Phrase: "He was excited about going to the concert next week." (The prepositional phrase ends with "going to the concert next week," another phrase)

The key element of a prepositional phrase is that it starts with a preposition (like "on," "to," "with," "in," "about") and modifies the noun or pronoun it follows. The final word in the phrase simply completes the preposition's meaning.