The gerund can be one of the most perplexing parts of language due to its varied use. Not every -ing word is a gerund, and the way a gerund is used in grammar changes according to the words preceding it, whether verbs, pronouns or others. Teaching a gerund requires delineation of seemingly arbitrary rules and understanding of verbal alternatives.

Discuss the idea of a gerund in English as basically an -ing word describing the noun form of a verb. Use and example such as swimming. While the word "swim" is a verb, the word "swimming" acts as a noun. Give several examples.

Explore how the use of a gerund co-exists with the use of the infinitive for many verbs. Use the example, "I like swimming" and "I like to swim."

Discuss the "want" verbs and other verb forms that can NOT use a gerund as opposed to the infinitive. Use the example, "I want to swim" NOT "I want swimming."

Briefly touch on the use of pronouns for "possessive" gerund cases. Use the example, "Their singing was wonderful."

Contrast -ing words that are NOT gerunds. Use the example, "I was swimming yesterday." Show how the words that are fixed in time are not gerunds because gerunds are more general words to describe the existence of an activity, for example, "I like swimming" is not fixed in time and does not provide chronological context.

For the explanation of time-fixed versus non-time-fixed verb forms, use a timeline to show how words that describe past actions are not gerunds but a continuous verb form. Examples: "I started swimming, I was swimming, I stopped swimming."

One more thorny manifestation of the "quasi-gerund" is harder to explain. Examples such as "I went swimming" or "I did some swimming" are on the border between describing time-fixed activities or the generic existence of the activity. Although these would probably best be described as gerunds, the opinions of linguists may differ.