Verbs can be broken down into different categories according to their specific functions and purposes. Two broad categories we can separate verbs into are finite verbs and non-finite verbs.
Finite verbs are verbs that do not need to be accompanied by other verbs. Finite verbs are directly related to their subjects and convey their tense, person, and number all on their own. They have one finite meaning that is conveyed completely with no assistance necessary from other verbs.
The dog dug a hole in the backyard.
The car gently rolled to a stop.
Albert eats his lunch alone at the picnic table.
The students play outside after lunch.
Notice how the verbs in the sentences above stand alone and need no other words to clarify their tense, person, or number. They are finite verbs because they are correct and complete without the help of any auxiliary verbs. Also notice that finite verbs are frequently located immediately after their subjects, but not always. In the second example, the adverb gently separates the subject car from the finite verb rolled.
Not many verbs are simple enough to be considered finite. Only verbs in base (infinitive form, or to form, without the to, like you would see them listed in a dictionary), simple past tense, and third person singular forms can stand alone as finite verbs.
You throw the ball. – base / dictionary form
They follow their leader. – base / dictionary form
Andrew tripped on his shoelaces. – simple past tense
You borrowed my pen. – simple past tense
Tim likes mint ice cream. – third person singular form
Susan travels all the time. – third person singular form
As you probably already guessed, non-finite verbs are verbs that can’t stand alone. Non-finite verbs do not fully convey tense, person, or number on their own and do not relate directly to their subjects. For example:
Miss Williams has written several articles recently.
The complete verb is has written. The non-finite verb is the past participle written because it can’t stand alone. It needs the auxiliary verb has to relate it to the subject and correctly convey its intended meaning in the sentence. We could not say, “Miss Williams written several articles recently.” No matter what we use as the subject or what time we are trying to refer to, we cannot make a correct sentence without an auxiliary verb to accompany written.
John is reading the newspaper.
The complete verb is is reading, and the non-finite verb is the present participle reading because it can’t stand alone. We couldn’t say, “John reading the newspaper.” Reading does not relate directly to the subject or show the right tense, person, or number by itself. There are many different auxiliary verbs that could be used before reading to form different numbers, tenses, and persons.
John was reading the newspaper.
John and Sam are reading the newspaper.
John has been reading the newspaper.
All of these are perfectly acceptable sentences using reading, but they all have significantly different meanings because they have different auxiliary verbs relating reading to one or more subjects and forming different tenses. However, by itself, reading does not correctly convey meaning in any of these sentences.