Modal verbs are easy to spot because there are so few of them. In addition to must, shall, will, should, would, can, could, may and might, we can add ought to and have to. If we are told that we 'must ...

Modal verbs, which express a likelihood, ability, permission, request, order etc., usually help main verbs to state the future. It is the reason they are categorised as auxiliary verbs in the context.

Mea culpa, mea culpa, mea minima culpa: Michael Bulley (Letters, 10 May) is right to correct me – Latin does have the modal verbs he names, which cover possibility (possum), permission (licet) and ...