School - How to define the functions of verbs and adverbs?

* The principle function of a verb in a sentence is to indicate "action":
You can "cook" well ; The dog "ate" my homework, etc.
* An adverb is a "modifier" in that it expresses a condition or manner relating to the verb:
You can "cook" (very) well ; The dog "ate" my homework (noisily), etc.