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What Are Auxiliary Verbs?

Auxiliary verbs (have/has) play a supporting role in sentences by joining participles to reflect tense/aspect/count/voice.

What are “auxiliary verbs”?

Auxiliary verbs, also called helper or helping verbs, do exactly what their name suggests: they help, or play a supporting role in sentences by complementing the main verb (which can be a participle form of a verb, or an infinitive). Auxiliary verbs can be complex, so let’s dive into the way they work, and understand these grammatical helping hands better!

What are the main auxiliary verbs?

The word auxiliary derives from the Latin word, auxiliaris, meaning “helpful, aiding”. This is precisely what helping verbs do: they support the work of the main verb by adding grammatical aspects, such as tense, voice, and count. The main auxiliary/helper verbs are:

To be and its verb forms (been/are/were/was/is)

do, does, did;  

Have, had, has;

While forms of be/have/do are all auxiliaries, and so can take on a supporting role in sentences, they are also complete verbs on their own. That means that they can be used in sentences as auxiliaries, or as the main verb. To identify whether these verbs are used as an auxiliary vs. as a main verb, check to see what other verbs are used in the sentence. If other verbs are included, most likely it’s the case that these verbs are used in the sentence as an auxiliary.

How to use auxiliary verbs

Read these sentences:

I go to school. (simple present tense; no auxiliary verbs.)

I am going to school. (present continuous)

I will have been going to school for 5 years in the fall. (future perfect continuous)

Let’s compare these sentences. The first sentence is in the simple present tense, and does not use an auxiliary. The simple present shows an action as currently taking place, or to communicate something as generally true or ongoing. For example, ‘I love chocolate’, ‘I play piano’, are examples of the  simple present tense; it communicates something as generally true irrespective of any particular point in time (or as taking place at that moment in time).

To show aspects of time, (or more complex aspects of time) we use auxiliary verbs. This is shown in the second and third sentence examples with the present continuous and future perfect continuous. The second sentence (present continuous or present progressive) uses the present participle form of the verb, which ends in –ing (going, playing, studying). The present continuous shows an action that began in the present, and is currently taking place in the present. The present continuous also shows actions as as ongoing/in progress:

I am reading a book.

I am playing the piano.

I am studying for my exam tomorrow.

I will be studying for my exam tomorrow. (future present continuous)

Notice that the present continuous tense uses forms of the auxiliary verbto be‘, rather than had or were/was (as these are past tense). The present perfect continuous, (example: I have been living in this house for 40 years), shows an event/action as having started at some point in the past but as continuing on into the future. To form the present perfect continuous aspect, use ‘has/have + been + the present participle (base verb + –ing). The sentence ‘I will be studying for my exam tomorrow’ is written in the future continuous tense, which refers to actions that will take place and be ongoing/continuous in the future.

Auxiliary verbs + perfect tenses

What is the perfect tense? When in doubt over the exact meaning of a word, look to its language of origin. The adjective perfect comes from the Latin word, perfectus, meaning “completed, excellent, accomplished, exquisite,” past participle of perficere “accomplish, finish, complete”. The perfect aspect or tense in is used to show actions that began at a point in the past but relates to the state of the present/future. This might sound confusing, so let’s take a look:

Present perfect tense:

I have done all my homework.

Toby has eaten all the cookies.

My mother has cut her finger.

Past perfect tense:

They had built another apartment building together.

The children had drawn beautiful sketches.

I had worked with Lucy for five years before she quit.

What’s the difference between the past perfect (also known as the pluperfect) and present perfect tense? First, the past perfect uses the auxiliary ‘had‘, whereas the present perfect uses have/has. This is because, as you may have guessed, the past perfect tense refers to an action or event that occurred and was completed entirely in the past. By contrast, the present perfect tense shows events that began in the past but are still ongoing in the present/future.  

The other notable difference is that the past perfect uses the past participle form of a verb + the auxiliary had, whereas the present perfect uses has/have + past participle form of a verb. The past perfect aspect in grammar is what forms the passive voice, and places the subject as a receiver of the action rather than the doer/actor.

Side-note: We often to refer to the past and present perfect as tenses, but it’s relevant to note that participles are not tenses in the strict sense of the term. Tense comes from tempus (Latin) meaning ‘portion of time’. As is clear from the above, the perfect aspect does not focus on the exact point in which the action took place, but rather on its resulting impact on the present or future.

What are modal auxiliary verbs?

There are also modal auxiliary verbs which reflect modes of being or mental states such as intent, necessity, will, and possibility:

  • can,
  • could,
  • may, might,
  • must, shall,
  • should, will, and would.

Learn more about verbs


1. Harper, Douglas. “Etymology of perfect.” Online Etymology Dictionary, Accessed 19 January, 2023.

2. The Present Perfect Tense

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