We learned that present progressive tense and past progressive tense both use verbs with an –ing ending.
Present progressive: I am working. You are working. She is working.
Past progressive: I was working. You were working. She was working.
Progressive tense uses helping verbs am, are, is, was and were.
Am, are, is, was and were are forms of the verb to be.
When these forms of the verb to be are put with another verb, they act as a helping verb.
I am running a race.
Running is an action verb, so in this sentence, am is a helping verb.
They are jumping rope.
Jumping is an action verb, so in this sentence, are is a helping verb.
Am, are, is, was, and were also work as linking verbs. Linking verbs are existence verbs.
We studied linking verbs in lessons 52 and 53.
When the linking verb links the subject to a noun that renames the subject, we call it a predicate noun.
Mom is a teacher. Teacher renames Mom.
This time, is works as an existence verb. There is no other verb, so is cannot be a helping verb.
When the linking verb links the subject to an adjective that describes the subject, we call it a predicate adjective.
Mom is smart. Smart describes Mom.
Again, is works as an existence verb. There is no other verb, so is cannot be a helping verb.
Remember: is, am, are, was, were are all forms of the verb to be. Sometimes these words are helping verbs and sometimes these verbs are linking verbs. If we want to know whether am is a helping verb or a linking verb, we need to look at the word that comes after am..
If an action verb comes after am, then am is a helping verb. I am going to school.
If a noun comes after am, then am is a linking verb with a predicate noun. I am an athlete.
If an adjective comes after am, then am is a linking verb with a predicate adjective. I am tired.