Auxiliary verbs: be, have and do

A helping verb and a main verb

A main verb tells you about an action or state. An auxiliary helps show such things as time, whether an action is continuing, or whether the sentence is a question. The auxiliaries do not all do the same job: be + -ing and have + a past participle give different information.

• The children are drawing a map.
• The children have drawn a map.

In the first sentence, are helps show an action in progress. In the second, have helps connect a completed action with now. Drawing and drawn are forms of the main verb draw. Do not choose an auxiliary just because it agrees with the subject; it must also fit the verb form and meaning.

The passive and longer combinations are introduced below as extensions. Use the linked tense pages to study their meanings in more detail.

Forms: choose the first verb carefully

The base form is the form you find in a dictionary: be, have, do, work, write. A past participle is the form used after perfect have: worked, written, gone. For a regular verb, the past and past participle both end in -ed. For an irregular verb, they may differ: wrote but written.

In an ordinary finite verb phrase, the first verb shows the tense and, where needed, agrees with the subject. The next verb has the form required by the verb before it. Finite means that the verb phrase is tied to a subject and a tense, as in she is working or they were working.

• My brother has packed the cups.
• My brothers have packed the cups.

The full forms in the table are not all interchangeable auxiliary forms. For example, auxiliary do in a present or past simple question is do, does or did. Done in I have done the washing is the main verb, not question-making do.

Be: continuing actions and passive forms

• I am carrying the empty boxes.
• They were checking the address.

Use the -ing form after continuous be, not the base form. Present am/is/are and past was/were help locate the action in time.

• The invitations were printed on recycled paper.

In this passive sentence, the invitations receive the printing action. Printed is a past participle, not an -ing form. A form after be is not automatically passive: in the window is open, open describes a state. Look at the meaning and the whole construction.

Be can also stand as the main linking verb, joining the subject to a description, identity or place: The hall is quiet; Her aunt is a pilot; The keys are upstairs. Main-verb be still makes its questions and negatives without do: Is the hall quiet?; The hall isn't quiet.

Have: perfect forms

• We have chosen a different route.
• The driver has brought the tickets.

Have is the auxiliary here. Chosen and brought are past participles. Do not replace them with choose or bring, or assume that every past participle ends in -ed.

Perfect have also appears in longer forms. Past perfect had + past participle looks back from a past time: The guests had left before the lights went out. Perfect continuous have/has/had been + -ing connects perfect and continuing meanings: We have been sorting the photos. These are extensions, not new meanings for every use of have.

As a main verb, have can mean own, eat or experience: I have a small balcony; We have lunch at one. For an ordinary question about ownership, Do you have a balcony? is a useful model. British Council also records Have you enough space? and I haven't much time. Do not call every main-verb have without do wrong. Have got has its own pattern: Have you got a balcony?.

Do: simple questions and negatives

• Does this lift stop on every floor?
• The children don't need another bag.
• Did the mechanic call yesterday?
• We didn't hear the announcement.

Use these patterns with ordinary main verbs when there is no other auxiliary. After does or did, the main verb stays in its base form: does she work, did she work. Do not put the third-person -s or past ending on both verbs.

Do can be both auxiliary and main verb in one sentence: What do you do on Saturdays? The first do makes the question; the second asks about the activity. In He doesn't do the accounts, doesn't makes the negative and do names the task.

Do not add do to an ordinary question or negative that already uses auxiliary be, perfect have or a core modal: Are they waiting?; Has she replied?; Can he drive? Main-verb be also needs no do: Were you at home? This is a rule for these statement and question patterns, not a claim that do can never come before be: negative commands such as Don't be late use a different construction.

Questions and negatives: use the first auxiliary

• Have the cleaners finished upstairs?
• The cleaners have not finished upstairs.

If there is more than one auxiliary, move only the first one before the subject. Put not after that first one in a negative statement. Keep the remaining verbs in their order.

• Has the road been closed? longer-chain extension
• The road has not been closed. longer-chain extension
• Will they be waiting outside? modal-chain extension

Core modals such as can, might and will share these question and negative patterns. They are not extra forms of do, be or have. They normally take a base verb: can leave, might be waiting, will have finished. Do not combine two core modals directly.

Do not turn question inversion into a rule for every question. When who is the subject, an ordinary question can be Who opened the drawer?, without do. A question inside another clause keeps statement order: Do you know where she is?

Short answers and words you do not repeat

In a short answer, keep the auxiliary and a suitable subject pronoun. Change you to I when answering about yourself. If the question uses ordinary present or past simple do, use the matching form of do in the answer.

• Are you joining us? Yes, I am.
• Has Marta sent the form? No, she hasn't.
• Did the boys tidy the room? Yes, they did.

With main-verb be, repeat be: Is the parcel heavy? No, it isn't. With a modal, repeat the modal: Can you reach it? Yes, I can. You can give a full answer too; short answers are a choice, not a ban on repeating the main verb.

Outside direct answers, an auxiliary can stand for words already understood: I haven't booked a seat, but my sister has. Here has means has booked a seat. A tag can also reuse the relevant auxiliary: You've checked the date, haven't you? Tags have their own rules, so see the separate page rather than adding a tag mechanically.

Short forms and emphatic do

An apostrophe can show missing letters: I'm = I am; we're = we are; I've = I have; hasn't = has not; didn't = did not. Cambridge describes these contractions as used in everyday speech and informal writing. Full forms remain possible.

Read the following verb to work out what 's or 'd means: She's waiting means she is waiting; She's finished the list means she has finished the list. I'd left means I had left; I'd leave means I would leave.

Use the full affirmative form at the end of a short answer: Yes, she is, not Yes, she's. Negative short forms can end the answer: No, she isn't. You can say either She isn't ready or She's not ready.

Stressed do, does or did can add force to an affirmative statement or correct a mistaken belief. Keep the next verb in its base form. It is not a question or a negative just because it contains do.

• You think I dislike the design, but I do like it.
• She did send the message; I saw the copy.

British Council groups it under an advanced section in its broad verb-phrase overview.

What comes next

Use am, is and are: the verb be in the present, The present continuous and The present perfect: form and uses for the basic forms; The passive: be + past participle for the passive; and Have and have got for possession. Practise question patterns on Question forms: yes/no and wh- questions and Subject and object questions. See Short answers, so do I, neither do I, and I think so, Question tags: isn't it? don't you? and Emphatic do, does and did for shorter replies, tags and emphasis. Each page keeps its own review status.