Unit 7.1

Have to: Modals of Obligation

Introduction

A modal verb is a type of auxiliary (helping) verb that has no meaning on its own but it modifies the main verb, changes its meaning and gives more details about actions.

Have to is a type of auxiliary modal verb used to express certainty, necessity or strong obligation which comes from outside, from external factors.

Form

Have to can be expressed in the three forms: affirmative, negative and interrogative.

Affirmative

Its structure, in the affirmative form, is:
Subject + have/has to + verb + …

  • Have/has: in the affirmative form, the third person singular changes from have to has.
Subject have/has to Verb
I/You have to work
He/She/It has to work
We/You/They have to work

Negative

Its structure, in the negative form, is:
Subject + do/does + not + have to + verb + …

  • Do/does: in the negative form, the third person singular changes from do to does;
Subject do/does + not have to Verb
I/You do not have to work
He/She/It does not have to work
We/You/They do not have to work

Short forms of the negative form are the same as the short form of present simple: I don’t – you don’t – he doesn’t…

Interrogative

Its structure, in the interrogative form, is:
Do/Does + subject + have to + verb + …?

  • Do/does: in the interrogative form the third person singular changes from do to does.
Do/Does Subject have to Verb Question
Mark
Do I/you have to work ?
Does he/she/it have to work ?
Do we/you/they have to work ?

Example

Affirmative:

  • The owner said I have to move to another house.
  • You have to buy a new fridge, the one you have is broken.
  • This has to be her flat! She said it’s floor 2, flat 13.

Negative:

  • You don’t have to clean your kid’s clothes everyday.
  • Alissa doesn’t have to search for a student flat.
  • We don’t have to sell the car.

Interrogative:

  • Do we have to clean the mess she made in the kitchen?
  • Do you have to paint the walls?
  • Do they have to complain about everything?

Use

We use have to to show that there is an obligation imposed by external factors.

It refers to:

  • A strong obligation (affirmative, interrogative);
  • A necessity (affirmative, negative, interrogative);
  • No necessity or no obligation to do something (negative);
  • Something is reasonably expected or is a certainty (affirmative, negative, interrogative).

 

Summary

The modal verb have to expresses certainty,  strong obligation, necessity or no obligation which comes from outside, from external factors.

We can use it in its different forms:

  • Affirmative: We start with the subject followed by have to and the verb. In the third person singular, we use has.
  • Negative: We start with the subject followed by do not have to and the verb. In the third person singular, we use does.
  • Interrogative: We start with do followed by the subject, have to and the verb (the sentence ends with a question mark). In the third person singular, we use does.

For example:
— Affirmative: “I have to go to school every day.” = The subject is obliged to go to school every day.
— Negative: “She doesn’t have to go to school every day.” = It is not necessary for the subject to go to school every day.
— Interrogative: “Does she have to go to school every day?” = We ask if the subject is obliged to go to school every day.

NOTE: Don’t have to (negative form of have to) usually expresses that something is not necessary to be done.

Let’s revise this content within the {Form} section. Take a look at the {Example} section that shows its use within a context.

Exercises