Expanding the Main Verb

When verb strings have just a single word, we call these verb forms the simple present and the simple past. But the verbs we use in our everyday speech and writing are often expanded forms that include auxiliaries, sometimes called helping verbs. In the sentence examples below, the auxiliary is shown in red; the main verb, in blue.

The students have been unhappy.	John may become a scholar.
The teacher has given us too much work.	The baby is sleeping upstairs.
The students should elect Barbara chairperson.	The students will study tonight.

We will be using the term predicating verb as a label for the entire verb string--including auxiliaries (if there are any) and the main verb--that fills the verb slot in the sentence pattern.

The following six auxiliary + main verb combinations represent only a small sample of the possibilities for expanding verb strings. With little or no effort our linguistic computer can come up with many other two-word variations--and with three- and four-word strings as well:

The students will be studying all afternoon.	The baby has been sleeping all morning.
They should have been studying harder.	Fred must have studied for his test.

In this examination of the verb, we want to understand the system underlying our ability to expand it as we do; we want to discover all the verb's possible expansions and to recognize the variations in meaning they can convey. Using to eat as our example, we will first look at some of the ways in which we use this verb in everyday situations.

I eat an apple every day.	I ate one this morning.
I have eaten an apple every day this week.	I should eat oranges as well.
My sister eats the seeds and all.	I am eating a peach at the moment.
I had eaten all the grapes by the time you arrived.	I was eating both candy and pretzels last night.
I have been eating junk food all evening.	I will eat only two candy bars today.
I might have eaten only one yesterday; I forget	I may be eating dinner at Carol and Jim's tonight.

This partial list of possibilities includes all the forms of the word eat itself: eat, ate, eats, eaten, eating. The only verb in English with more than five forms is be, with eight: be, am, are, is, was, were, been, being.

To emphasize form rather than meaning, we will rename the five verb forms.

Form	New Label	Traditional Label
1. eat	the base form	present tense
2. eats	the -s form	3^rd-person singular, present tense
3. ate	the -ed form	past tense
4. eating	the -ing form	present participle
5. eaten	the -en form	past participle

A comparison of eat, which is an irregular verb, with the regular verb walk will provide the rationale for the labels -ed and -en.

1. base form	eat	walk
2. -s form	eats	walks
3. -ed form	ate	walked
4. -ing form	eating	walking
5. -en form	eaten	walked

In the language of traditional grammar, a verb is regular when both its simple past tense and its past participle forms (forms 3 and 5) are formed by adding the inflectional ending -ed (or in some cases -d or -t); this means that the past tense and the past participle of regular verbs are always identical in form. This description applies to most verbs. Only a small number, one hundred or so, are irregular, although, like eat, they are among the verbs we use most frequently. The regular past tense inflection (-ed) provides the label for the past tense; the -en form of irregular verbs such as eat (and drive, give, break, speak, choose, etc.) provides the past participle label.

The subtle differences in verb meanings we are able to express result not from variations in the verb itself, with its limit of five forms, but rather from the auxiliaries we add. Here again are the versions of eat that we used in the sentences above:

1. eat	5. eats	9. was eating
2. ate	6. am eating	10. will eat
3. have eaten	7. had eaten	11. might have eaten
4. should eat	8. have been eating	12. may be eating

To discover the system underlying these verb strings, we will make some observations about these twelve variations of eat, observations that apply to all verbs in English, both regular and irregular.

1. The base form is used alone in [1] and with should [4] and will [10].
2. The -ed and -s forms are used alone in [2 and 5].
3. The -en form is used after a form of have: had [7] and have [3, 8, and 11].
4. The -ing form is used after a form of be: am [6], been [8], was [9], and be [12].

Observations [3] and [4] can be stated as a formula: (have + -en) + (be + -ing)

This formula means that we can use have as an auxiliary, but when we do, we follow it with the -en form of the verb. It also states that we can use the -ing form of the verb, but when we do, we precede it with a form of be. The parentheses mean that have + -en and be + -ing are optional auxiliaries; that is, a well-formed verb string does not require either or both of them.

Based on the twelve variations of eat, we can make some more observations:

1. eat	5. eats	9. was eating
2. ate	6. am eating	10. will eat
3. have eaten	7. had eaten	11. might have eaten
4. should eat	8. have been eating	12. may be eating

5. If you choose both have and be [8] as auxiliaries, they appear in that order, first have and then be.
6. Besides have and be, we have another kind of auxiliary: should [4], will [10], might [11], may [12]. We call this kind of auxiliary a modal auxiliary, and we will represent them in verb string formulas as M.
7. When a modal appears, it is the first word in the verb string.

Now we can add another element to the formula: (M) + (have + -en) + (be + -ing)

Once again, the parentheses mean "optional." That is, if we choose a modal auxiliary, it comes first; if we choose have as an auxiliary, it is followed by an -en form of the verb; if we choose be as an auxiliary it is followed by the -ing form of the verb. But we do not have to choose any of these elements to produce a grammatical verb string.

One last observation:

1. eat	5. eats	9. was eating
2. ate	6. am eating	10. will eat
3. have eaten	7. had eaten	11. might have eaten
4. should eat	8. have been eating	12. may be eating

8. A form of eat, the main verb, represented in the formula by MV, is the last word in the verb string.

And we can add another element to the verb expansion formula: (M) + (have + -en) + (be + -ing) + MV

Because it is not optional, MV is not in parentheses; all verb strings have a main verb.

Interpret the formula in this way: In generating a verb string, we can use a modal auxiliary if we choose; when we do, it comes first. We can also choose have; when we do, the -en form follows it. We can also choose be; when we do, the -ing form follows. When we use more than one auxiliary, they appear in the order give: modal, have, be. Notice too that the -en and the -ing get attached to whatever follows, for example have + -en + be + -ing + go produces have been going.

But something is still missing from our formula. How can the formula generate had eaten and was eaten? Had and was are past tense (-ed) forms of have and be. So we have to add one more component to the formula: tense, which refers to time. Among the five forms of the verb, you will recall, the present and the past forms are the only tenses, so T will represent either present or past tense. Here, then, is the complete formula for the verb expansion rule:

T + (M) + (have + -en) + (be + -ing) + MV

T is the tense marker that attaches itself to whatever follows it--that is, to the first word in the string, either M, have, be, or MV. Notice as well that T is not in parentheses; like a main verb, tense is not an option in a grammatical verb string. So to generate had eaten, and was eating, we choose past as the tense marker:

past + have + -en + eat = had eaten
past + be + -ing + eat = was {were} eating

When there is no auxiliary word intervening, the tense gets attached to the main verb, thus producing either the simple past tense or the simple present.

past + eat = ate
pres + eat = eat {eats}

The modal auxiliaries differ from the auxiliaries have and be, both of which can fill the role of the main verb in addition to their auxiliary role. The modals never fill the main verb slot, nor do they have all five forms that verbs have. They have a maximum of two forms, the base, which is also the present tense, and the -ed. To formulate the tense of a modal, we will pair them, assigning the base form and present tense to one, and the -ed (or past tense) to the other:

Base and pres Form	-ed Form	Base and pres Form	*-ed Form*
can	could	will	would
shall	should	may	migiht

According to our formula, T (M) + (have + -en) + (be + -ing) + MV, if we choose M, the modal auxiliary will carry the tense marker:

past + will + eat = would eat
pres + shall + eat = shall eat
past + can + have + -en + eat = could have eaten
past + can + have + -en + be + -ing + eat = could have been eating
pres + will + be + -ing + eat = will be eating

T (M) + (have + -en) + (be + -ing)

Here is what the completed formula says:

In generating a verb string, there are only two requirements--tense (either present or past) and the main verb; the other components are optional. The tense marker will apply to the first word in the string. We have the option of using three different kinds of auxiliaries: modal, have, and be. When we use more than one, we use them in that order. The formula also specifies that with have we use the -en form of the following auxiliary or verb; with be, the -ing form of the following verb. The last word in the string is the main verb.