Sometimes in English, a verb is used as a noun. When the verb form is altered and it serves the same function as a noun in the sentence, it is called a gerund.
Gerunds
A noun created from the ‐ing form of a verb can act as a subject or an object in a sentence.
Sleeping sometimes serves as an escape from studying.
The gerunds sleeping and studying are ‐ing forms of the verbs sleep and study. Sleeping is a noun functioning as the subject of this sentence, and studying is a noun functioning as an object.
Problem Gerunds
Gerunds can sometimes be difficult to use correctly in a sentence. What problems can you have with gerunds?
When a noun or pronoun precedes a gerund, use the possessive case of the noun or pronoun.
Jana's sleeping was sometimes an escape from studying.
To test for correct usage, substitute the noun in place of the gerund. For example, in the preceding sentence, replace the gerund sleeping with the noun slumber. Read these sentences aloud and listen for the difference.
Jana's slumber was sometimes an escape from studying.
not Jana slumber was sometimes an escape from studying.
Even when you think that the word before the gerund looks like an object, use the possessive case.
Jana was annoyed by Bill's studying.
not Jana was annoyed by Bill studying