Question

Choose the most suitable modal verb for this sentence:
You __________ speak only when you’re spoken to. (compulsion)
a) Ought to
b) must
c) Dare to
d) Used to

Answer 1

Hint:A modal verb is an auxiliary verb (such as `can' or `will') that is used to express modality. For example- can, should, must, may.

Complete answer:
In the given question, we have to select which of the given options contains the correct modal verb that describes compulsion. Let us thus analyze the options given to us in this question:
Option (a.), 'ought to', refers to ‘(auxiliary) indicating duty or obligation.’
Therefore, option (a.) is incorrect as compulsion is not indicated by this modal.
Option (b.), ‘must', refers to ‘(modal auxiliary, defective) to do as a requirement; indicates that the sentence subject is required as an imperative or directive to execute the sentence predicate, with failure to do so resulting in a negative consequence’.
Therefore, option (b.) is correct as this correctly indicates that there is a compulsion to do something.
Option (c.), ‘dare to', refers to ‘take upon oneself; act presumptuously, without permission’.
Therefore, option (c.) is incorrect as this is not a modal verb.
Option (d.), ‘used to', refers to ‘in the habit of doing something’.
Therefore, option (d.) is incorrect as this is not a modal verb.

Note:
In this question, it will be helpful for the students to recall the concept of modality. Modality is a classification of propositions on the basis of whether they claim necessity or possibility or impossibility.