True or False: The modal verb 'ought' changes form based on the subject.

False. 'Ought' does not change form and remains the same for all subjects.

Fill in the blank: 'Need' is generally followed by an infinitive without ___ when used as a modal verb.

'to'

Explain how 'must not' is used in sentences.

'Must not' is used to indicate prohibition, expressing that something is not allowed or forbidden.

What does the phrase 'you ought to have' imply regarding past actions?

It implies a realization that the correct or sensible action was not taken in the past.

Fill in the blanks: 'Have to' and 'had to' are used to express ___ and ___ in the present and past, respectively.

Obligation and necessity

How does 'need not' express absence of obligation?

'Need not' indicates that there is no requirement or necessity for an action, suggesting that it is optional.

What does the modal verb 'could' imply in terms of ability or possibility?

'Could' expresses a past ability or a possibility in the present or future, depending on the context.

Explain the function of 'have to' in logical conclusions.

'Have to' indicates a necessary inference or reasoning based on circumstances, suggesting that something must be true.