"Juanitas good driving prevented an accident." I think ..... verb is "to prevent" as you say. accident could be a noun and thus an object, possibly a direct object. verb "to drive" written as "driving" is, I think, a gerund (which is a verb used as a noun). maybe "helping verb" and "gerund" are similar ? I think that "an" is an article of the noun "accident". Definite would be "The accident.". Indefinite would be "an accident". I think....