"Is is a linking verb."
That seems to be a commandment of grammar that was drilled into people's minds by every well-meaning teacher.
The problem is that it's not entirely accurate. It would be more accurate to say, "Is can be a linking verb." or "Is often acts as a linking verb."
The truth is that is can also be a helping verb or an intransitive complete verb.
We'll go over each of those sentences, and I'll show you how they work.
Note that this lesson applies other forms of to be (am, are, was, were) as well.
The job of a linking verb is to link the subject with either a noun that renames it (predicate noun) or an adjective that describes it (predicate adjective). In this example, is is linking Henry with the adjective happy. It's saying Henry = happy.
Because it's clear that the predicate adjective happy refers to the subject, we know that is in this sentence is linking.
More linking verb examples
Helping verbs are verbs that "help" the main verb in the sentence. That means that they don't carry the weight of the meaning of the verb. In this case, walking is the main verb and is is a helping verb.
More helping verb examples
This is the one that trips people up. There are three types of action verbs (you learn about all of them in our Get Smart program), and in this case, is functions as an intransitive complete action verb.
This means that the verb doesn't transfer its action to anyone or anything. It is complete all by itself.
If that's hard to wrap your head around, a synonym for is in this case is exists. (Henry exists here.)
More intransitive complete action verb examples
Other Helpful Resources