* Pronouns replace nouns (people, places, things) in a sentence. Examples include: he, she, it, they, we, you, I, etc.
* Adjectives describe nouns or pronouns. Examples include: popular, big, red, beautiful, etc.
Here's how you might use "popular" in a sentence:
* The popular restaurant was crowded. ("Popular" describes the restaurant, which is a noun.)
Let me know if you have other questions!