Here's why:
* Gerund: A gerund is a verb ending in "-ing" that functions as a noun. In this case, "twirling" is the gerund.
* Object of a Preposition: The object of a preposition is the noun or pronoun that follows a preposition (like "from," "to," "with," etc.).
* Analysis: In the sentence "The child was dizzy from twirling," the preposition is "from," and the gerund "twirling" is the object of the preposition.
Let's look at the other sentences:
* their free time children enjoyed drawing. "Drawing" is the object of the verb "enjoyed."
* teacher encouraged reading. "Reading" is the direct object of the verb "encouraged."