So far we have avoided discussing an important feature of the verbal groups which we have looked at in this section. This is the feature known as the FINITE element. This refers to the morpheme inflection which signifies simple tense in either main verbs or auxiliaries. It is not an independent element, but is always attached to an auxiliary or main verb.

We shall discuss this more fully in the following section, but for the moment we can refine our analysis by stating that this morpheme must be present in the mood structure of the verbal group. If we represent the finite element as "f", we can then show the structure of a finite verbal group as follows, where the bracketing "[]" indicates that the f morpheme is not a separate element in the structure, but is incorporated in the morphology of the initial element in the group.

Where no auxiliary is present, then the finite is fused with the main verb and shown as a morpheme inflection.

If an auxiliary is present, then the finite is expressed as an inflection of the initial auxiliary, and is separated from the main verb:-

We can then define mood structure most simply as consisting of:

SUBJECT + FINITE.

It is thus the structural relationship between these two elements which determines mood selection, and English requires that in the formation of interrogative mood the finite element must always precede the subject. With the sole exception of the verb BE, the finite element is separated from the main verb in the interrogative. The structure of the indicative mood forms should then be amended as follows:-

FINITE AND NON-FINITE

Verbal groups choose between finite and non-finite.

Finiteness is expressed through two systems - PRIMARY or SIMPLE TENSE and MODALITY.

The division between these systems is not entirely distinct however, and there is considerable overlap in meaning and function. However, we can summarise the semantic and structural contrasts briefly as follows:-

(1) In principle, the system of primary tense relates the verbal group to a fixed time reference, as provided by other features of the text or situational context; the system of modality typically expresses a range of attitudes and influences such as probability, possibility, certainty, obligation, necessity and so on.

(2) Primary tense is signified through a system of inflections, either in the main verb or operator, whereas modality is expressed by the modal verbs.

However, tense is not restricted to functioning in terms of time reference, and has wider implications. Neither is time reference restricted to tense, for it may also be signified by modal verbs - specifically by WILL / SHALL for future time, and USED TO, COULD and NEEDED for past time. There is also an element of prediction inherent in the notions which are expressed in modality, which is clearly associated with futurity.

We shall consider these systems separately in more detail, but before we say more about the functions which distinguish finite from non-finite structures, we should be clear precisely what forms these may take. There are three forms which the finite verb may take, and four forms for the non-finite, which are referred to as follows:-