you can add any of the following to the beginning of the rhyme and still have a grammatical sentence
Up to this point we haven't really needed phrase structure rules. They are convenient and precise way of specifying syntactic structures , but we could have achieved the same result by merely specifying the finitely many legal tree structures in the grammar, with all other structures implicitly disallowed. However, once we acknowledge the unboundedness of sentences, we need a formal device to specify each legal structure; there are infinitely many.
To see how this work, let us first look at the case of multiple prepositional phrases such as [ The girl walked [down the street][over the hill][through the woods]... VP substructures currently allow only one PP per sentence () We can rectify this problem by revising rule 5
Rule 5 is different from the previous rules because it repeats its own category(VP) inside itself . This is an instance of a recursive rule. Recursive rules are of critical importance because they allow the grammar to generate an infinite set of sentences.
Reapplying rule 5 shows how the syntax permits structures with multiple PPs, such as in the sentence ' The girl walked down the street with a gun toward the bank
you can add any of the following to the beginning of the rhyme and still have a grammatical sentence
Up to this point we haven't really needed phrase structure rules. They are convenient and precise way of specifying syntactic structures , but we could have achieved the same result by merely specifying the finitely many legal tree structures in the grammar, with all other structures implicitly disallowed. However, once we acknowledge the unboundedness of sentences, we need a formal device to specify each legal structure; there are infinitely many.
To see how this work, let us first look at the case of multiple prepositional phrases such as [ The girl walked [down the street][over the hill][through the woods]... VP substructures currently allow only one PP per sentence () We can rectify this problem by revising rule 5
Rule 5 is different from the previous rules because it repeats its own category(VP) inside itself . This is an instance of a recursive rule. Recursive rules are of critical importance because they allow the grammar to generate an infinite set of sentences.
Reapplying rule 5 shows how the syntax permits structures with multiple PPs, such as in the sentence ' The girl walked down the street with a gun toward the bank
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