Identify the italicized phrase in the sentence below. His hobby is writing poetry. This phrase is a (n) : infinitive phrase prepositional phrase participial phrase gerund phrase

In the sentence "His hobby is writing poetry," the phrase "writing poetry" is a gerund phrase. A gerund phrase is verb + ing which functions as a noun. In the sentence, the phrase "writing poetry" is a noun acting as a complement of the subject.

His hobby = writing poetry. This means "writing poetry" complements the subject "His hobby".