Here's why:
* Relative pronouns do introduce adjective clauses. Adjective clauses modify nouns or pronouns, providing additional information about them. Examples:
* The book *that I bought yesterday* was very interesting. (The clause "that I bought yesterday" describes the noun "book")
* The woman who lives next door is a doctor. (The clause "who lives next door" describes the noun "woman")
* Relative pronouns can introduce noun clauses, but only in a specific case. Noun clauses function as nouns and can be subjects, objects, or complements in a sentence. They are introduced by relative pronouns when they act as the object of a preposition. Examples:
* I'm interested in what you said. (The clause "what you said" is the object of the preposition "in")
* We discussed who should lead the project. (The clause "who should lead the project" is the object of the preposition "about")
Important Note: While relative pronouns can introduce noun clauses in the specific case above, they are more commonly used to introduce adjective clauses.
Let me know if you'd like to explore more examples!