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4-1 Expressing Necessity

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ENGL120 - Unit 4

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I've got to return these books to the library.

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Modal Verbs

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  • Modals are auxiliary verbs with special meanings:

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  • can
  • ought (to)
  • could
  • must
  • would
  • may
  • should
  • might
  • will
  • shall

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  • Modals are different from normal verbs. They don't use an s for he / she / it

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Examples

  • He cans go to the store.
  • He can go to the store.

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  • They make questions by changing the order of the words in the sentence.

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Examples

  • She can go.
    • Can she go?

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  • They are followed directly by the base form of another verb (without to) (*ought to is the only exception)

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Examples

  • He must goes.
  • He must going.
  • He must to go.
  • He must go.

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Other Expressions

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  • English has many other expressions used in a similar way to modal verbs:

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  • be going to
  • have to
  • be allowed to
  • have got to
  • be able to
  • be supposed to
  • had better

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Expressing Necessity

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  • We can use verbs such as must, have to, or have got to to say when something is necessary.

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Examples

  • Children must do their homework.
  • Children have to do their homework.
  • Children have got to do their homework.

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  • Be careful of the differences in form:

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must

have to

have got to

Positive

He must go to work.

He has to go to work.

He has got to go to work.

Negative

He must not work.

He doesn't have to go to work.

He hasn't got to go to work.

Question

Must he work?*

Does he have to work?

Has he got to work?

*Questions with must are not common.

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must

have to

have got to

Positive

You must do your homework.

You have to do your homework.

You have got to do your homework.

Negative

You mustn't do your homework.

You don't have to do your homework.

You haven't got to do your homework.

Question

Must you do your homework?*

Do you have to do your homework?

Have you got to do your homework?

*Questions with must are not common.

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  • In spoken English, have to is often pronounced, "hafda" or "hafdo." Has to is often pronounced, "hasda" or "hasdo". Have got to is often reduced to "gotta."

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  • Have to, have got to, and must all express that it is necessary to do something.

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  • Must is usually stronger in meaning and can express urgency or importance.

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Examples

  • I have to go home.
  • I've got to go home.
  • I must go home. (stronger in meaning)

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  • Because must has a stronger meaning, it is less common in spoken English when describing necessity.

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  • English speakers usually prefer have to or have got to. Must is more common in writing.

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  • There is no past form of must or have got to.

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  • Instead, use had to.

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Examples

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  • I must study.
  • I have to study.
  • I have got to study.
  • I had to study. (past)

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Lack of Necessity

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  • To say that it isn't necessary to do something, we use do not have to or have not got to. To talk about the past, we use did not have to:

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Examples

  • The concert is free. You do not have to pay to enter.
  • I don't have school tomorrow. I don't have to go to bed early tonight.
  • We haven't got to hurry. There's still lots of time.

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Examples

  • Last night, I didn't have to make dinner because my mother took me out to a nice restaurant.
  • Jane didn't have to do any homework because she had finished everything during class.

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Prohibition

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  • Using must in the negative has a very different meaning. It means that something is prohibited.

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  • This means you cannot do it, you are not allowed to do it, or it is bad to do it.

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Examples

  • You mustn't eat in Mr. James' class.
    • You are not allowed to eat in Mr. James' class.

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  • You mustn't drink alcohol with this medicine.
    • It is bad to drink alcohol with this medicine.

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Examples

  • You mustn't start without me.
    • Don't start without me.

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  • Notice the difference between must not and do not have to:

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  • You mustn't leave.
  • You don't have to leave.
  • Don't leave!
  • You can leave if you want, but it is not necessary.

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Optional Review Video

Expressing Necessity

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