I am learning English grammar (parts of speech), and encountered this sentence:

Kolkata is a big city.

where "is" represents a verb. Could you please help me to understand why?

  • 7
    "is" is the present form of the verb "be".
    – keshlam
    Nov 15, 2022 at 3:34
  • 2
    It's part of the same irregular verb, whose present infinitive is "to be". I am, you are, it is; I was, you were, it was; I will be, you will be, it will be... and so on.
    – keshlam
    Nov 15, 2022 at 4:23
  • 2
    @nigel222 The definition of a verb is not restricted to words conveying action, so there's no need to wrestle with the attempt to describe existence as an action. Verbs can simply convey a state of being ("is", "tastes", "smells", "lies", "sits", etc), not just an action. Many verbs can be used in either sense. ("I smell a flower", "The flower smells nice")
    – chepner
    Nov 16, 2022 at 15:56
  • 5
    Just curious: Would you share what's your native language? Does it not have the equivalent verb?
    – vashekcz
    Nov 16, 2022 at 16:53
  • 1
    @DawoodibnKareem But that isn't the question the OP is asking. They are asking how we know the second word in the sentence is a verb. And that is not irregular, because it's the most basic structure of English grammar. You could put any other word there, and it would still be recognised as a verb. The sentence might not make sense with some words :) but the first thought of everyone who speaks English would be that it was a verb.
    – Graham
    Nov 17, 2022 at 8:24

3 Answers 3


We are often told that verbs are 'action words' and that nouns represent 'things' and stuff like that. It's not true! Verbs, nouns and adjectives and so forth are words that share certain grammatical properties. The word is in Kolkata is a big city doesn't represent any kind of action. However, it is a verb because it is a member of the verb category and shares the same grammatical properties as other verbs.

In English, verbs usually have the following properties (amongst others):

Verb forms:

Most verbs have the following different verb forms:

  • present and past tense forms, e.g. walk/walked, go/went

  • a third person present tense form ending in < s >, e.g. walks, goes

  • an -ing form (a gerund-participle), e.g. walking, going

  • a past participle, e.g. walked, gone

  • a base form (used in infinitives, imperatives and subjunctives), e.g. walk, go

In the Original Poster's example, the word is is the third person singular present tense form of the verb be. The verb be has all of the forms described above (and more!):

  • are/were
  • is
  • being
  • been
  • be


  • In a declarative sentence, the verb usually appears after the subject: She likes cheese

In the OP's sentence the word is appears after the subject, Kolkata: Kolkata is ...


  • In the present tense, the verb form must agree with the grammatical/semantic number of the subject:
  1. The elephant eats buns. (singular subject, 3rd person single verbform)
  2. The elephants eat buns. (plural subject, plural verbform)

In the OP's sentence we see a singular subject Kolkata and the singular verb from is. If we made the subject plural we would need the plural form are:

  1. [Kolkata and New York] are big cities.

Necessary element of sentence

  • Every well-formed sentence in English must have a verb, and every declarative sentence must have a tensed verb.

In the Original Poster's example, Kolkata is a noun, and a big city is a noun phrase, so the verb must be the word is!:

  1. Kolkata is a big city.

Be is an auxiliary verb

More than being a mere verb, we can show that the verb be (and therefore the word is) is a member of a very special group of verbs, the auxiliary verbs. People used to think an auxiliary was a verb that came before another verb. Nowadays we know that auxiliary verbs are verbs that share special grammatical properties. It doesn't matter whether there's a following verb:

Auxiliary verbs

Auxiliary verbs have four special properties:

They contract with not, and are necessary to negate sentences:

  • She likes cheese.
  • *She likesn't cheese. (ungrammatical)
  • Kolkata is a big city.
  • Kolkata isn't a big city.

They change places with the subject to make yes/no sentences:

  • *Likes she cheese? (ungrammatical)
  • Is Kolkata a big city?

We can use an auxiliary verb without the rest of the verb phrase, so long as the listener can understand the missing words:

  • A: Do you like Cheese? B: *I like cheese! (ungrammatical)
  • A: Is Kolkata a big city? B: It is a big city!

We stress auxiliary verbs to emphasise that a sentence is true:

  • She likes cheese. (weird pronunciation)
  • Kolkata is a big city. (emphatic).

So not only is the word is a verb in the Original Poster's example, it is an elite member of the auxiliary verbs!

  • 4
    -` the verb "to be" can, and often does, serve as an Auxiliary verb. But in the sentence "Kolkata is a big city" it is the main verb, not an auxiliary verb. Nov 15, 2022 at 20:35
  • @DavidSiegel May I humbly suggest that you consult a modern vetted C21st grammar source, such as The Cambridge Grammar of the English Language or A Student's Introduction to English Grammar? or see John Lawler's post here. Or see Is 'Helper Verb' Old School. Or consult Ivan Sag et al's (2020) Lessons from the English Auxiliary System? Nov 15, 2022 at 21:19
  • 2
    Just because it's the only verb doesn't mean it's not an auxiliary verb (according to Wikipedia, one that "adds functional or grammatical meaning to the clause in which it occurs, so as to express tense, aspect, modality, voice, emphasis, etc.") "is" provides a stative aspect to the sentence, if I am applying this definition correctly.
    – chepner
    Nov 16, 2022 at 16:03
  • In this already long answer you didn't address the comparison with "Kolkata is growing".
    – Florian F
    Nov 18, 2022 at 11:38
  • @FlorianF I can't quite see how that would address the OP's question. Could you explain? Nov 18, 2022 at 14:14

In English the copula, "be", is a verb.

In other languages, the copula is not a verb. For example, Korean.

The word "be" has forms: be, am, is, are, was, were, being, been.

"Is" is the third-person present form of "be".


"is" is part of the verb to be: (singular) I am; you are; he/she/it is; (plural) we are; you are; they are.

In this context "be" indicates an existence of some sort.

The meaning of *Kolkata is a big city" approximates to Kolkata exists as a big city.

The use of "is" (and the rest of the verb "to be") is to supply a verb to a sentence like this because, in general terms, all sentences must have a verb.

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