STRUCTURES WITH ONE GRAMMATICAL AUXILIARY: O V
In the finite VG with only one auxiliary, this auxiliary is necessarily the operator and, according to its type, selects a corresponding form of the lexical verb. The o v structure can express the following features of grammatical meaning, in addition to the obligatory choices of tense, finiteness, polarity and contrastiveness:
And with a lexical auxiliary:
5 be + about to + V-inf is about to drive
The four basic combinations also combine with each other to make up more complex Verbal Groups, all of which function as one VG at Finite + Predicator in clause structure. The features modal, perfect, progressive, passive occur in ordered combinations, like the letters of the alphabet ABCD. Thus, for instance, B can follow A, or D can follow C, but not vice versa. A certain feature may be omitted, as in ACD, BD. Lexical auxiliaries can occur with any combination.
