STRUCTURES WITH THREE GRAMMATICAL AUXILIARIES: O X X V
15 modal + perfect + progressive must have been driving
16 modal + perfect + passive must have been driven
17 modal + progressive + passive must be being driven
18 perfect + progressive + passive has been being driven
Verbal groups of three grammatical auxiliaries are more common in speech than in writing. With a modal or a lexical auxiliary, complex forms easily occur in spoken English, as in the following examples:
. . . and (they) think the killer could be being protected locally [KIE]
The matter could and should have been dealt with as set out above [FD6]
Groups with the two forms been being are uncommon, but they can occur if they are needed.
With a lexical auxiliary added there are now four auxiliaries:
19 modal + perfect + lexical-aux must have been about to drive
20 modal + lex.-aux + progressive must be about to be driving
21 modal + lex.-aux + passive must be about to be driven
22 perfect + lex.-aux + progressive has been about to be driving
23 perfect + lex.-aux + passive has been about to be driven
24 progressive + lex.-aux + passive is about to be being driven
Then his application would have to have been made to the Commission by March. [FBK]
We will go no further with the structure of the finite extended VG, as no examples of five auxiliaries have been found in a large corpus. In principle, however, there is no grammatical constraint on their composition and the telescoped order of elements allows for their use if the context requires them.
