A gerund is an ‘ing’ verb that functions as a noun, as in the sentence “I enjoy running.” Gerund phrases, as in the sentence “Running through the park is my favorite activity,” are phrases that function as whole nouns. There are two types of gerund phrases: simple and complex. Simple gerund phrases, like the previously used example “Running through the park is my favorite activity,” use the gerund as a noun, but the gerund phrase can be used as a verb phrase:
As Noun: “Running through the park is my favorite activity
As verb: I am running through the park.
Complex gerund phrases are quite different. They often placxe an article (a or the) or an adjective in front of the gerund, and sometimes, the phrase employs an of-prepositional phrase:
Complex Gerund Phrase: The Running of the Bulls was quite a sight to see.
Notice that the gerund phrase, in this case, cannot be used as a verb phrase (i.e. I cannot say “I am Running of the Bulls). It’s important to distinguish between complex and simple gerund phrases because we cannot make them parallel to each other even if they are both gerunds
Incorrect: I enjoyed sitting in the park and the viewing of the meteor shower.
Correct: I enjoyed siting in the park and viewing the meteor shower.