Verb phrase

The predicate of a clause in English is filled by what can usefully be called a ‘verb phrase’ (VP); this is a string of verbs. (An alternative use, which is not followed here, is to say that the VP also includes an object NP.) A VP must include a main verb as head. This may optionally be preceded by auxiliary verbs: either do, or any or all of:

It is, then, at least theoretically possible to say might (i) have (ii) been (iii) being (iv) beaten (head).

The first word in a VP inflects for tense, e.g. has/had broken, is/was breaking, is/was broken. Negation is shown by not or -n’t, which must follow the first auxiliary verb, e.g. can’t break, isn’t breaking, hadn’t broken. If none of the auxiliary elements (i)–(iv) are present then do must be included with a negative, e.g. broke, didn’t break. If a VP does not include a negation or any of (i)–(iv) then do may be included to carry emphasis, e.g. He did go. (Note that do is incompatible with any or all of (i)–(iv), except in an imperative, where one could say, for instance, Do be sitting down when they arrive!).