Here's why:
* Pronouns replace nouns. They refer to people, places, or things that have already been mentioned in a sentence. For example, "The dog barked. It ran away." "It" replaces "the dog".
* Verbs show action or state of being. They describe what the subject of a sentence does or is. For example, "The dog barked." "Barked" is the verb describing the action of the dog.
Example:
* Incorrect: "The dog barked. It did it loudly." (Pronoun "it" seems to replace the verb "barked").
* Correct: "The dog barked. It barked loudly." (Pronoun "it" replaces "the dog" and the verb "barked" is repeated).
Let me know if you have any more questions about pronouns or verbs!