Here are some examples:
* Swimming is a great way to exercise. (The gerund "swimming" is the subject of the sentence)
* I enjoy reading novels. (The gerund "reading" is the object of the verb "enjoy")
* He is good at cooking. (The gerund "cooking" is the object of the preposition "at")
Gerunds can function as the subject, object, or object of a preposition in a sentence. They often describe an activity or action.