* "lay" (her backpack on a chair): This is a transitive verb. It takes a direct object ("backpack"). The action of laying is being done to something specific.
* "laid" (down on bed): This is also a transitive verb. It takes a direct object, even though it's implied. The action of laying is being done to the subject (Valeria) on a specific thing (the bed).
Key Takeaway:
* Transitive verbs require a direct object to receive the action.
* Intransitive verbs don't have a direct object. They simply express an action.
Let me know if you have any other sentences you'd like to analyze!