* Gerunds are verb forms ending in "-ing" that act as nouns.
* Nouns can be used in various ways within a sentence: subject, object, object of a preposition, appositive, etc.
Examples:
* Subject: _Swimming and diving are my favorite water activities._ (Both "swimming" and "diving" are gerunds acting as subjects)
* Object: _I enjoy reading and writing._ (Both "reading" and "writing" are gerunds acting as objects of the verb "enjoy")
* Object of a preposition: _He's great at hiking and camping._ (Both "hiking" and "camping" are gerunds acting as objects of the preposition "at")
Key point: The number of gerunds in a sentence depends on the structure and complexity of the sentence. As long as the gerunds are grammatically correct and fulfill a noun function, you can have multiple gerunds in one sentence.