In English grammar, what is the function of a helping verb?

A helping verb, also known as an auxiliary verb, plays a crucial role in providing additional meaning and context to the main verb in a sentence. It can indicate aspects such as time, mood, voice, or even the modality of the action. For instance, in the sentence "She is running," the helping verb "is" helps convey the present continuous tense, indicating that the action is ongoing. By using helping verbs like "is," "have," or "will," sentences can express subtleties about when actions take place or the state of being more effectively.

The other functions presented do not describe the role of a helping verb accurately. Changing the main verb tense primarily involves the main verb itself and its forms rather than the helping verb alone. While a helping verb can be essential in creating certain tenses, its specific function is not solely about changing tense. Similarly, a helping verb does not act as the primary verb; instead, it supports the main verb. Lastly, separating independent clauses is the role of conjunctions or punctuation rather than helping verbs. Thus, the primary function of a helping verb is to enhance the main verb with additional meaning.