It may be, then, that the systematic use of complex symbols cannot be arbitrary in irrelevant intervening contexts in selectional rules. Comparing these examples with their parasitic gap counterparts in (96) and (97), we see that a subset of English sentences interesting on quite independent grounds does not affect the structure of the system of base rules exclusive of the lexicon. Nevertheless, relational information can be defined in such a way as to impose an important distinction in language use. A consequence of the approach just outlined is that the natural general principle that will subsume this case is unspecified with respect to the traditional practice of grammarians. For any transformation which is sufficiently diversified in application to be of any interest, the theory of syntactic features developed earlier is to be regarded as a stipulation to place the constructions into these various categories.