Catalog
The standard auxiliaries are BE, HAVE, and DO. Each of these can also be main verbs, but this article focuses on their role as auxiliary verbs. In addition to the standard auxiliaries, English also has modal auxiliaries.
BE
The auxiliary BE is particularly unique in two ways. The first is that it has an irregular present verb form and multiple past forms, each depending on the person and count of the subject:
- infinitive form: ‘be’
- present forms: ‘am’ (1st-person singular), ‘is’ (3rd-person singular), and ‘are’ (2nd-person singular; all plurals)
- past forms: ‘was’ (1st-person or 3rd-person singular) and ‘were’ (2nd-person singular; all plurals)
- active participle: ‘being’
- perfect/passive participle: ‘been’
The second way that BE is unique is that it can act as the main verb and an auxiliary at the same time. Whenever BE is the main verb of a clause (as in, “Hannah is tall.”) and there are no other auxiliary verbs, then that same BE can take on the role of an auxiliary by hosting negators (“Hannah isn’t tall.”), inverting positions with the subject (“Is Hannah tall?”), and so on.
As an auxiliary, BE is featured in the forms of both continuous tenses — where it must be followed by an Active Participle form — and Passive Voice — where it must be followed by a Passive Participle form.
HAVE
The auxiliary HAVE has the following verb forms:
- infinitive form: ‘have’
- present forms: ‘have’ (1st-person and 2nd-person singular; all plurals) and ‘has’ (3rd-person singular)
- past form: ‘had’
- active participle: ‘having’
- perfect/passive participle: ‘had’
As an auxiliary, HAVE is featured in the forms of perfect tenses and perfect modals. I both cases, HAVE must be followed by a Perfect Participle form.
While HAVE can be either a main verb or an auxiliary, the same instance of HAVE cannot be both at the same time. Therefore, we sometimes have two HAVEs in a verb chain (as in “have had” or “have been having”) — the first as an auxiliary, and the second as the main verb.
In some dialects of British English, HAVE can be both a main verb and an auxiliary verb simultaneously, just like BE. Consider the examples “Have you any wool?” or “I haven’t any answers for you.”
DO
The auxiliary DO has the following verb forms:
- infinitive form: ‘do’
- present forms: ‘do’ (1st-person and 2nd-person singular; all plurals) and ‘does’ (3rd-person singular)
- past form: ‘did’
- active participle: ‘doing’
- perfect/passive participle: ‘done’
While DO can be either a main verb or an auxiliary, the same instance of DO cannot be both at the same time. Therefore, we sometimes have two DOs in a verb chain (as in “do do” or “did do”) — the first as an auxiliary, and the second as the main verb.
As an auxiliary, DO is not associated with any grammar topic or verb construction in particular. Instead, DO serves as a backup auxiliary. If we need an auxiliary verb for structural reasons (such as hosting a negator or inverting for a question form) but wouldn’t already use one for tense, voice, etc., then we use DO to fill that role. The auxiliary DO should be followed by a bare infinitive.
Modals
Modal auxiliaries are used to express modality: they reveal the speaker’s level of and type of conviction regarding the verb phrase. For instance, modals can express speculation, obligations, volition, habits, and more.
The core modal auxiliaries are:
can • could • may • might • must • shall • should • will • would
In addition, we have the marginal modals dare, need, had better, ought [to], and would rather, which have most but not quite all of the characteristics of the core modals.
And then there are the pseudo-modals get, have, have got, need, and tend, which serve similar purposes to modals but feature few of the characteristics of modal verbs. Moreover, these pseudo-modals cannot be used as auxiliary verbs.
Visit the Modal Verbs page to learn more.
The core modals should always be followed by bare infinitives, while pseudo-modals should be followed by full infinitives (marginal modals are split between these two). We also have Perfect Modals, which usually convey either the past or an unreal mood, depending on the modal flavor. Perfect Modals combine modal auxiliaries with a following ‘have’ (as in “may have”, “would’ve” , “ought to have”, etc.).
| auxiliary | followed by | featured in |
|---|---|---|
|
BE |
an Active Participle |
Continuous Tenses |
|
a Passive Participle |
Passive Voice |
|
|
HAVE |
a Perfect Participle |
Perfect Tenses |
|
DO |
a Bare Infinitive |
(if no other auxiliaries) |
|
Core Modals |
a Bare Infinitive |
certain moods |
|
Pseudo-Modals |
a Full Infinitive |
Auxiliaries in Verb Chains
Verb Chains is the term Insights uses to incorporate a main verb and all its auxiliaries, along with any negators (see the following section). Complete verb phrases may have multiple verb chains, and they may include adverbs or other modifiers. But here, we narrow our focus just to verb chains.
Order
Auxiliaries within a verb chain come in a certain order:
modals → Perfect HAVE → Continuous BE → Passive BE → main verb
Most verb chains do not include all of these elements, but whichever elements are included should come in this order. For instance, we might say “have been waiting“, but not “be having waited“.
The first auxiliary verb in any verb chain is the leading auxiliary. If a modal is included, it should be first, and is therefore the leading auxiliary. If no modals are included, then the leading auxiliary would be HAVE (if it’s included), and so on. Leading auxiliaries carry out special roles, as explained in the next section.
Following Forms
The form of any verb in a verb chain, whether it’s an auxiliary verb or the main verb, depends on which auxiliary precedes it:
- The verb following a Passive BE should be in the Passive Participle form.
- eg: “is given“
- The verb following a Continuous BE should be in the Active Participle form.
- eg: “is giving“; “is being given“
- The verb following a Perfect HAVE should be in the Perfect Participle form.
- eg: “has given“; “has been given“; “has been giving“; “has been being given“
- The verb following a modal should be in its infinitive form. If it’s a perfect modal, then it includes HAVE, which should be in its base infinitive form, and then the following verb should be in its Perfect Participle form.
- If there are no auxiliaries before a verb, then that verb should be in a basic present or past form.
As you can see, the form of any one verb may vary depending on tense, modality, and voice. The form of a verb doesn’t depend on the meaning of that verb itself, but rather on which auxiliary precedes it.
Leading Auxiliaries
The leading auxiliary is what Insights to English calls the first auxiliary verb of any verb chain. While the auxiliaries BE, HAVE, and modals play important semantic roles in certain grammar topics like tenses or voice, the leading auxiliary in particular plays an additional syntax role in the structure of the clause. The leading auxiliary is essential to question forms, short answers, negatives, and more.
Hosting Negators & Adverbs
Any verb phrase is made negative with the inclusion of negators. In English, our prime negators are ‘not‘, ‘never‘, and occasionally ‘no longer‘. If one of these negators is included in a verb chain, it comes immediately after the leading auxiliary; it cannot come any earlier or later within the verb chain.
If the speaker chooses, the negator ‘not‘ can be contracted as ‘n’t‘ and affixed to its leading auxiliary (unless that auxiliary is may or certain marginal modals).
While most modifiers would be placed outside the verb string, certain adverbs can come in the midst of their verbs. Adverbs of Degree, Frequency, or Modality are typically be placed after the leading auxiliary, but before any following auxiliaries and the main verb. For example, “have often been told,” or “have allegedly been told.”
If a leading auxiliary shifts around the sentences (as with inversion — see below), ‘not‘ can move with it, especially if it’s contracted. However, other adverbs instead stay with (and just before) the rest of the verb chain. For example: “Haven’t you been working all weekend?”; “Have you really been working all weekend?”
Subject-Auxiliary Inversion
Question Forms
Many question forms — including Polar Questions, Predicate ‘WH’ Questions, and Question Tags — feature subject-auxiliary inversion, which means that the leading auxiliary comes before the subject. For example, while a declarative sentence might be “Martha is going to the store,” the corresponding Yes/No Question would be “Is Martha going to the store?” and the corresponding Predicate Question would be “Where is Martha going?” See how ‘is’ — which comes after the subject (‘Martha’) in declaratives — instead comes before the subject for these question forms?
No matter how many auxiliaries a verb chain may have, only the leading auxiliary should be placed in front of the subject whenever there’s inversion.
More Inversion
While the most common application of subject-auxiliary inversion is in certain question forms, we can also use it in a few other ways:
- in counterfactual Condition Clauses to express an unreal mood. For instance, “Had she known better, …” carries the same meaning as “If she had known better, …”
- for negative expressions. For instance, “Never have I been so insulted!” means the same thing as “I have never been so insulted!” Negative inversion is required for certain clausal coordinating conjunctions, as in “No sooner did we arrive home than it began to rain.”
- in brief expressions of accord or parity that begin with the words ‘as’, ‘neither’, or ‘so’.
- These may take the form of short sentences, as in “You play tennis? So does Gloria!” See the Ellipses section below for details.
- Or these may take the form of Comparison Clauses. For instance, “as am I,” means “I am also [previously stated predicate].”
Note that inversion expressions like these are increasingly less common among most modern English speakers, at least in casual speech.
Notes on Inversion
- Subject-auxiliary inversion is necessary for certain grammatical structures, which means that an auxiliary must be included. If there would otherwise be no auxiliary verbs available (for tense, mood, or voice), then:
- use DO, …
- unless BE is the main verb, in which case it can also be the leading auxiliary.
- Occasionally, an inverted auxiliary also hosts a negator, as with Negative Questions or Question Tags. If there’s a 1st-person subject and the auxiliary is BE, the contracted form of “
amn’t” is not acceptable, so there are two possible alternatives:- Don’t form a contraction. This results in “am I not“, which is incredibly formal.
- Replace ‘am’ with ‘are’, as in “aren’t I”. Negative inversions are the only times that ‘are’ can accompany ‘I’.
Ellipses
Sometimes a voiced sentence includes only a segment of the understood verb phrase. This is called an ellipsis. Whatever parts of the verb phrase are removed should be clear from context, almost certainly because they were expressed before (often earlier in the same sentence or in the previous sentence). The piece of the verb phrase that must remain is the leading auxiliary … potentially along with any negators.
The most common type of ellipses is Short Answers. Following the question, “Who is calling you?” a full answer might be “Dave is calling me.” But in many cases, English speaker will use a Short Answer instead of the full one: simply “Dave is.” Here, the leading auxiliary ‘is’ represents the full predicate “is calling me”, but the rest of that phrase doesn’t need to be voiced since it’s already known from the question.
Short Answers usually end with the leading auxiliary, or else the following negator. For example, the question “Can Monica juggle?” is probably answered by either “Yes, she can,” or “No, she can‘t.”
In some British English dialects, Short Answers and other ellipses cannot end with modal verbs, but instead use DO after a modal. For instance, where we might say “Yes, she could’ve,” and “It might,” in American English, the corresponding sentences in British English might be “Yes, she could’ve done,” and “It might do.”
Ellipses are also used in expressions of Comparison or Contrast. Here are some examples with the omitted parts in brackets:
- “Eloise has donated blood more often than Jennifer has [donated blood].”
- “Micah won‘t have any extra screwdrivers, but Charles will [have extra screwdrivers].”
- “I didn’t used to exercise as much as I do [exercise] now.”
- “Cats can climb trees, whereas dogs can’t [climb trees].”
Ellipses can be used be used in Echo Questions, which are typically used to express disbelieve or ask for clarification. For example, given the statement, “Polly isn’t working there anymore,” an echo question in response would be “She isn’t?”
And finally, Ellipses are used to express parity. For example:
- “Sarah went to that concert last night.” ⇨ “So did I!”
- “I couldn’t believe Vance hit a home run! ⇨ “Neither could he!”
- “My sister is a doctor.” ⇨ “Mine is, too.”
DO Support
Given that leading auxiliaries are essential for certain types of sentence structure, what happens if there are no auxiliaries in the verb chain?
This is precisely what DO is for.
DO is a dummy auxiliary, meaning that it has no semantic role. DO doesn’t contribute any meaning to the verb phrase, and it’s not important for any tense, voice, or mood.
But DO can play a role in the syntax/structure of a clause if no other auxiliaries are available to do so.
Consider how this sentence (which originally features no auxiliaries) includes DO in different ways as it is used for different purposes:
- original sentence: “I like pizza.”
- negative statement: “I don’t like pizza.”
- yes/no question: “Do you like pizza?”
- negative question: “Don’t you like pizza?”
- short answers: “Yes, I do [like pizza].” / “No, I don’t [like pizza].”
- ‘wh’ question: “What kind of pizza do you like?”
- comparative: “I like pizza even more than John does.”
Sometimes would could be used instead of DO. Often, would makes the verb phrase hypothetical. But would is also used in questions and answers that communicate offers or requests, especially if they need to sound deferential.
Agreement
The leading auxiliary must agree with the subject of that clause. Subject-Verb Agreement means that the form of the first verb of a verb string (whether it’s a main verb or an auxiliary verb) should take on a form dependent upon the person or count of the subject.
- for Non-Past:
- for Singular subjects:
- for 1st-Person subjects: am | have | do | can
- for 2nd-Person subjects: are | have | do | can
- for 3rd-Person subjects: is | has | does | can
- for Plural subjects: are | have | do | can
- for Singular subjects:
- for Past:
- for Singular subjects: was (1st– & 3rd-person) / were (2nd-person) | had | did | could
- for Plural subjects: were | had | did | could
Core modals and marginal modals are unique among English verbs in that their form is the same regardless of the perspective or number of the subject. For instance, we would say “I might”, “she might”, “we might”, etc. Pseudo-modals, however, change their form in the same way that regular verbs would (eg: “you get to”, “he gets to”).
Additional Properties
Contractions
Many forms of auxiliary verbs can be contracted and affixed to their preceding subjects. Common contractions include:
- ‘m = am
- ‘s = is or has
- ‘re = are (or, less commonly, were)
- ‘ve = have
- ‘d = had or would
- ‘ll = will
Emphasis
While not essential to grammatical structure, adding emphasis helps the speaker express their message and their style. In speech, we usually emphasize by saying a particular word or syllable louder, longer, or at higher pitch than the rest. In writing, we might bold, italicize, or underline a word to emphasize it.
In many cases, emphasizing an auxiliary verb can help get the speaker’s point across. Emphasizing BE or HAVE can reinforce that aspect of tense, while emphasizing a modal underlines the strength of the modality. The leading auxiliary can be emphasized to call make a negative clear, or in the case of no negators, to make the speaker’s affirmation clear.
Once again, if no auxiliaries would otherwise be included, DO can be added to host the emphasis, as in “I do plan on returning the sweater I borrowed.”
Teaching Tips
Identification
By the time you introduce the term ‘helping verb’ or ‘auxiliary verb’, students should already be familiar with BE and DO, if not HAVE, can, and will as well. For some learners, simply calling out the auxiliaries they already know will be enough.
If you need another quick way for learners to identify auxiliary verbs, ask them what words they know that n’t can be attached to. Since we can’t contract not with main verbs, any examples learners can come up with must be auxiliary verbs.
Auxiliaries are Important
Don’t sideline auxiliaries when discussing various grammar topics. For example, the Present Continuous tense isn’t simply the -ing form; without BE, it’s not the Present Continuous form (in fact, the -ing form would instead be a verbal, which has very different applications). Be quick to correct students who leave off the BE from attempts at continuous tenses — it’s not a minor mistake; the auxiliary is crucial both for understanding and for structure.
The same is true for HAVE in perfect tenses and BE in Passive Voice.
Shifting Perspectives
When we take a sentence and shift it’s perspective, the leading auxiliary verb is usually the part that changes the most. We can see this in…
- shifting from present to past (backshifting)
- shifting from one speaker to another (as in Reported Speech)
- shifting from positive to negative
- shifting from interrogative to declarative
You may find that simple shifting exercises at early levels may help students develop their sense of structure. Other times, shifting may be called for in particular grammar topics.
Insider Access
Visit our How to Teach Helping Verbs grammar series on www.insightstoEnglish.com for demonstrational videos, bonus notes, printouts, slideshows for your class, practice activities, and more.
Further Reading
Encyclopedia Pages
Insights Articles
Lexical Classes (Parts of Speech)
Noun Phrases: Determiners • Adjectives • Nouns • Pronouns
Verb Strings: Auxiliary Verbs {Modal Verbs} • Adverbs • Verbs
Subsets of Verbs: Linking Verbs • Stative Verbs • Irregular Verbs
Linkers: Conjunctions • Adpositions
