9.56 USAGE NOTE

With passives, 'be' is often, but not always, kept after a modal.

• He argued that if tissues could be marketed, then anything could be.

However, with perfect passives, you can just use the auxiliary 'have' or 'has'. For example, you could say, 'Have you been interviewed yet? I have'.

Note that when a modal with 'have' is used for a passive or continuous verb group, 'been' cannot be omitted.

• I'm sure it was repeated in the media. It must have been.
• Priller noticed that they were not flying in tight formation as they should have been.

9.57

If the second verb group contains the auxiliary 'have' in any form, you can add 'done' to the group. For example, instead of saying 'He says he didn't see it but he must have', you can say 'He says he didn't see it but he must have done'.

• When these questions are satisfactorily answered I might perhaps view their infantile behaviour more charitably than I have done to date.
• It would have been nice to have won, and I might have done if my concentration hadn't lapsed.

Similarly, you can use 'do' after modals.

• It makes a click like the lid of a tin may do.

Note that when the verb used in the first mention of an action or state is the main verb 'have', instead of using 'do' after a modal in the second mention, you often use 'have' instead.

• 'Do you think that academics have an appreciation of the administrative difficulties of running a University?' --- 'No, and I don't think they should have.'

9.58

Usually ellipsis occurs in a clause which comes after a clause in which the action or state has been mentioned with a main verb. Occasionally, however, for a deliberate effect, the clause containing the ellipsis comes before the clause explicitly mentioning the action or state.

• If, as they should be, directors are themselves scholars, they will appreciate the language that scholars use.