Modals of Obligation

Modals of Obligation

Why and how do we use them?

We use must when we make the rules

I must get a good night's sleep tonight.

Open Ended

Can you make your own example about your own rules?

We use have to when we talk about other people's rules

You have to buy a ticket before you get on the train

Open Ended

Can you make your own example about other people's rules?

The is no past or future form of must. When we talk about rules in the past or the future we use the correct for of have to.

When you go to India, you'll have to get the visa.

I had to wear a uniform at school.

Open Ended

Can you make your own example about the future or past?

Some tips

• Don't use contractions with have to. I have to go NOT I've to go

• There is not much difference between must and have to. Have to is more common, especially in spoken English.

• Have got to is also used in spoken English and it means the same that have to.

• Questions with must are very rare.

Mustn't, can't and don't have to

We use mustn't or can't when something is not allowed.

We use mustn't when we make the rules and can't when others do.

I mustn't forget to email my mom.

I can't cross the road yet - the light's still red.

Open Ended

Make an example where you make the rules.

Open Ended

Make an example where others make the rules.

We use don't have to when there is no obligation.

University students don't have to wear a uniform.

Open Ended

Make an example where something is not necessary.

Should and ought to

We use should and ought to when we give advice or recommendation. They have the same meaning but should is more common.

We should see as much as possible. We shouldn't waste time.

We ought to see as much as possible. We ought not to waste time.

Open Ended

Make an example giving an advice or recommendation

The End

Complement with exercises 6A in page 143.