TSA CBT Practice Test 2025 – The Complete All-in-One Guide for Exam Success!

A gerund is defined as a verb form that ends in -ing and functions as a noun. This definition captures the essence of what a gerund is and how it operates within a sentence. For instance, in the sentence "Swimming is fun," the word "swimming" is derived from the verb "swim" but acts as the subject of the sentence, fulfilling the role of a noun.

In contrast, other options do not accurately describe a gerund. A verb tense combined with an adjective does not align with the nature of gerunds, which are purely about the verb form acting as a noun. A clause that must be included in a sentence pertains to different grammatical elements, such as dependent or independent clauses, rather than gerunds. Lastly, a phrase that describes a noun refers to adjectival phrases, which is also distinct from the function of gerunds. Therefore, the correct understanding of a gerund is best captured by the definition provided in the correct answer.