As with some of our other rules, the grammar requires us to add restrictions
that cannot be written into the expressions. For example, the dependent clause
marker is only optional in the context of S, and NP in the Sis optional only in
the presence of VP. Bare infinitives only appear with certain kinds of verbs,
such asmake,and tense is optional only in a VP.
The necessity of adding these extra-rule restrictions is clearly a problem
for phrase-structure grammar. The grammar would be more elegant, perhaps,
if we could write the rules in such a way as to include these restrictions, but no
one has figured out how to do that. As we approach the end of this chapter, it
may be tempting to anticipate the next by intuiting that transformational-gen-
erative grammar solves the problem of restrictions. In this case, however, in-
tuition would be wrong.
PHRASE STRUCTURE GRAMMAR 157
Sentence 4.80: Macarena answered slowly,not to be coy but to be clear.