by JonathanSchneider Wed Nov 19, 2008 8:36 pm
An -ing form can play one of four roles: part of a verb, noun (gerund), adjective, or adverb. To be part of a verb, it must be accompanied by some form of the verb "to be." As a gerund, it is a standalone noun; we sometimes, but not always, use the word "the" to emphasize that the word is to be read as a noun. If it is simply modifying a noun, it is an adjective, and it will generally be right next to that noun without a comma. If it is following a comma (but not part of a list), it is most likely an adverb; in this case it will often introduce a longer adverbial modifier.
Because the -ing form after a comma is usually read as an adverb, we often include an article such as "a" or "the" before the -ing form when we mean it as a noun. In this case, it can in fact be parallel with other nouns. I can think of a couple of examples from the OG where we have -ing nouns set parallel with other nouns. What keeps these parallel is more than just the fact that they are nouns; they are also action nouns (nouns that suggest some sort of action, for instance: "the ripping.")