The verb in the imperative
Another important structural feature of the imperative is that it uses the base form of the verb, with no modals or tense-aspect forms. This is shown by the use of be in Be careful ! (not *are (being) careful, *can be careful). The grammatical status of the base form as a non-finite is somewhat problematic, however. It does not share functions with other non-finite verb forms; rather, the imperative has more in common, functionally, with finites than with the non-finites. Like interrogatives, it relates the speaker to the hearer and to the here-and-now, typically in face-to-face interaction.
Because the base form is indistinguishable from some declarative forms, there is potentially structural ambiguity between an imperative with a you-subject and a declarative. This is disambiguated only in speech, by stress on the imperative subject:
A How do we get tickets for this show?
B You go and stand in the queue/ AmE in line. (unstressed, declarative, use of ‘generic’ you = ‘one’)
A What shall we do, then?
B You go and stand in the queue while I park the car. (stressed, imperative)
There is, however, a distinction between declarative and imperative when the verb is be, as in role-taking. This is because be has retained different forms for person and tense (am, is, are). Compare:
You be the doctor and I’ll be the nurse. (imperative)
You’re the doctor and I’m the nurse. (declarative)
The declarative 3rd person singular finite form -s avoids ambiguity with a 3rd person subject imperative. Note however that please always points to a directive meaning:
If the Subject is plural, the verb form is the same in both types, but intonation, pause, gesture and common sense serve to clarify the meaning in a specific context.
Ticket-holders (pause) come this way! Ticket-holders come this way.
Those in agreement (pause) raise their hands! Those in agreement raise their hands.
