Which of the following words is NOT a common helping verb?

• A. am
• B. have
• C. will
• D. run

Answer: (D)

This question tests your ability to tell apart auxiliary (helping) verbs from the main verb. Helping verbs pair with a main verb to show tense, aspect, or mood. Am is a form of be and is used as an auxiliary in phrases like I am studying. Have functions as an auxiliary to form perfect tenses, as in I have finished. Will is a modal auxiliary that indicates future action, as in I will go. Run, however, is a basic verb that describes an action by itself and does not carry auxiliary function. It can be the main verb in a sentence like I run every morning, but it doesn’t help another verb tense or aspect. So run is not a common helping verb.