Verbs express action, we were told in the third grade (those of us who got taught grammar in the third grade). And it is true that some verbs do express action.
Emma shot the pirate.
Daniel danced all night.
Verbs also express a state of being, however:
My uncle is a fireman
Jeffery seems upset.
Or a static condition:
I have a red Mustang.
Elliot speaks French. (Not as in, he’s speaking it right this minute, but as in, he knows how to speak it, and he’ll speak it for you whenever you like.)
As we noticed with dogged, some words that aren’t verbs can act as verbs – can undergo a functional shift to act as a verb from time to time, in other words. So, just as with nouns, it’s helpful to have a few proofs to tell whether a word in question is a true verb, or whether it’s some other word that is just, in this specific case, functioning as a verb.
On page 78 in your text, you’ll see the proofs for testing whether a word is a verb or not. Just as with the proofs for a noun, no verb will pass all of these proofs. So long as they pass two or more of them, though, they’re either a verb (if they pass the form proofs) or functioning as a verb in this case (if they only pass the functional proofs).
Verb proofs (from page 78)
1. Has a verb-making morpheme (criticize)
2. Can occur with the present tense morpheme (bakes)
3. Can occur with the past tense morpheme (baked)
4. Can occur with the present-participle morpheme (baking)
5. Can occur with the past-participle morpheme (had baked)
6. Can be made into a command (Bake!)
7. Can be made negative (He didn’t bake today.)
8. Fits one of the two frame sentences:
They must ___________ (it)
They must ___________ good.
The three verb subclasses have to do with how verbs function in English sentences. These classes are intransitive, transitive, and linking verbs, and they’ll be discussed later.