Modal Auxiliary Verbs 3

Marginal Modals

Used to

This is used
- to express something that existed or was done in the past but no longer exists or is done now.

Examples
He used to go jogging when he was younger.

Ought to/ Oughtn't to

This is used
- to express a duty or obligation.

Examples
You ought to pay for the vase that you broke.

- to express a possibility

Examples
If we leave now, we ought to be there in an hour time.

- to express an advice

Examples
You ought not to have shouted at her.

- with a perfect infinitive to express an unfulfilled duty or action.

Examples
He ought to have finished his work before going out to play.

- with 'have' to show disapproval of a completed past action.

Examples
She oughtn't to have disobeyed her parents.

Dare/Daren't

This used
- to express one's courage or lack of courage in doing something.

Examples
Dare you do it?
I daren't ask him about it.

Need/Needn't

This is used
- in negative sentences to show that somethinging is not necessary (It is replaced by 'must' in affirmative sentences)

Examples
You needn't help them but I must.

- in interrogative sentences (It is replaced by 'must' in affirmative sentences)

Examples
Need I come too?
Yes, you must.