Here are some examples:
* I went to the store. (I replaces the noun "person")
* He is my friend. (He replaces the noun "friend")
* They are going to the park. (They replaces the noun "group of people")
* This is my favorite book. (This replaces the noun "book")
* Someone is at the door. (Someone replaces the noun "person")
Pronouns are very important in language because they help us avoid repetition and make our sentences more concise.