Final answer:
The gerund 'swimming' functions as the subject of the sentence 'Swimming at the beach is safe most of the time.'
Step-by-step explanation:
The function of the gerund in the sentence 'Swimming at the beach is safe most of the time' is that it is the subject of the sentence. Gerunds are verb forms that function as nouns, and in this case, 'swimming' acts as the subject of the sentence, indicating the action or activity being discussed. The gerund phrase 'swimming at the beach' functions as the subject of the sentence, providing the main focus of the sentence. A gerund is an -ing verb form that functions as a noun in a sentence. In this case, 'Swimming' is the main action but is being used like a noun to tell us what the sentence is about, which is the activity of swimming. Therefore, like any noun within a sentence, it serves as the subject that the verb ('is') agrees with.