In order for a sentence to be complete, it needs to have a noun phrase and a verb phrase. Generally speaking, the noun phrase indicates who or what the sentence is fundamentally about; the verb phrase contains whatever the sentence tells us about that. Of course there are more complex sentence structures with multiple noun and verb phrases, but let us focus on the simplex structure for the moment.
A noun is a word which signifies a person, place, thing, or abstract idea. A verb, however, is more difficult to define. Many people define a verb as an "action word." This definition is not so much incorrect as it is incomplete; most verbs signify actions, but a few do not. Take a look at the following sentences:
1. Juan plays football with his friends.
2. Juan played football with his friends.
1. Mrs. Poulos is a science teacher.
2. Mrs. Poulos was a science teacher.
The first pair of sentences each contains an action; the act of playing. "Play," therefore, is an action word; it is the verb in those sentences. However, neither sentence in the second set contains an action; instead, they each indicate a state of being. In other words, they tell us what Mrs. Poulos is (or was), but not what she does (or did). In order to tell us what Mrs. Poulos does or did, the sentences would have to be written as:
1. Mrs. Poulos teaches science.
2. Mrs. Poulos taught science.
So, can we define a verb in such a way as to create a single definition which covers all verbs, including the ones which are not action words?
Note that in each pair of sentences, all of the words remain the same from one to the next, except one which changes as a result of changing from present to past tense. This is true regardless of whether the verb indicates an action or not. So, let us define a verb as a word which indicates the tense (past or present) of a sentence; or, a word whose form changes as a result of a change in tense.
[Note: There is no true future tense in English. To create the future tense, we need to add auxiliary words like "will" or "shall" to the infinitive form of the verb; the verb itself does not change form. "Will" and "shall," and other auxiliaries like "can" and "may" are not considered verbs themselves. They are auxiliaries in the present tense; the past-tense variants are "would," "should," "could" and "might," respectively.]
Now, how can we tell if a verb indicates an action or not? Since we generally write in the past tense, let's look at sentences #2 and re-designate them:
A. Juan played football with his friends.
B. Mrs. Poulos was a science teacher.
The verbs in these sentences are "played" and "was," respectively. We know that because these are the words that changed as a result of tense in the above examples. But can they both be called "action words" as well? There's an easy way to find out. We'll call it the "Verb-of-Doing Test."
For each sentence, you need to ask the following question: What did [the subject] do?
In sentence A, the subject is Juan. Juan played football with his friends. What did Juan do? He played football with his friends. The original sentence itself answers the question.
The subject of sentence B is Mrs. Poulos. Mrs. Poulos was a science teacher. What did Mrs. Poulos do? We can't answer this question; the sentence doesn't present an action on the part of Mrs. Poulos, it merely presents her in the condition of being a science teacher. It can be inferred that Mrs. Poulos taught, but this is only suggested; the sentence doesn't actually say that. If anything needs to be changed or added to the original sentence in order to answer the question, the sentence fails the test.
Sentence A, therefore, passes the Verb-of-Doing Test. Sentence B does not, so what we have is a verb-of-being. There are eight basic verbs-of-being: be, become, remain, live, have, cost, weigh, and measure. (Was, of course, is a past-tense singular conjugation of be.)
When writing stories, it's important to use at least one verb-of-doing in every sentence, and avoid using verbs-of-being. Verbs-of-being can be used in essays, but it's usually more effective to use verbs-of-doing even in expository writing. (Click here for a more detailed lesson on this point.)
NOTE: It is possible to turn a verb-of-doing into a verb-of-being and thus fail the verb-of-doing test.
A. Manjit stood by the door.
B. Manjit was standing by the door.
Sentence A passes the test (What did Manjit do? She stood by the door), but sentence B does not (What did Manjit do? We don't know; all we know is she was standing by the door when she did it.)
By using the passive, compound form was standing instead of the active form stood, the writer can no longer answer the question with the sentence as written.
The verb in sentence A is stand. In the present tense it would read, Manjit stands by the door. (Stood changes to stands as a result of tense.) But in sentence B, the verb is be (conjugated as was); in present tense, Manjit is standing by the door. Was changes to is; standing remains the same, so by our definition, the actual verb is now be, not stand. Sentence B, therefore, fails the verb-of-doing test. It presents a condition rather than an action.
THE TEST IS: "What did [the subject] do?" The original sentence, as written, must be the answer to this question.
THE TEST IS NOT: "What was [the subject] doing?" THIS IS NOT THE TEST!!! If the sentence answers this question but not the one above, it is a VERB-OF-BEING and does NOT pass the Verb-of-Doing Test.
When writing stories, always be wary of using the "was ____ing" form of any verb. If you do use it, make sure there is a verb-of-doing in the same sentence with it, for example:
Jamarr was eating lunch when he heard a strange sound.
What did Jamarr do? He heard a strange sound. He was eating lunch at the time, but the verb-of-doing here is heard (or, hear).
Verbs of doing should also be used as much as possible in literary essays; click here.
See also: Show, Don't Tell; Momentary Acts; Establishing Setting; Revealing Character.