Phrase strure rule（短语结构规则）

Phrase-structure rules were used in early transformational grammar (TGG) to describe a given language's syntax.They were used to break a natural language sentence down into its constituent parts (also known as syntactic categories) namely phrasal categories and lexical categories (aka parts of speech).Phrasal categories include the noun phrase,verb phrase,and prepositional phrase; lexical categories include noun,verb,adjective,adverb,and many others.Phrase structure rules were not an invention of TGG; rather,early TGG's defining characteristics were those systems which it had in addition to phrase structure rules (the most obvious example being transformations; see the page transformational grammar for an overview of the development of TGG.) A grammar which uses phrase structure rules is called a phrase structure grammar.
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Definition
Phrase structure rules are usually of the form A to B quad C,meaning that the constituent A is separated into the two subconstituents B and C.Some examples are:
S to NP quad VP
NP to Det quad N1
N1 to (AP) quad N1 quad (PP)
The first rule reads:An S consists of an NP followed by a VP.This means A sentence consists of a noun phrase followed by a verb phrase.The next one:A noun phrase consists of a determiner followed by a noun.
Further explanations of the constituents:S,Det,NP,VP,AP
Associated with phrase structure rules is a famous example of a grammatically correct sentence.The sentence was constructed by Noam Chomsky as an illustration that syntactically but not semantically correct sentences are possible.
Colorless green ideas sleep furiously can be diagrammed as a phrase tree,as below:
Colorless green ideas sleep furiously.
where S represents a grammatical sentence.
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Alternative approaches
A number of theories of grammar dispense with the notion of phrase structure rules and operate with the notion of schema instead.Here phrase structures are not derived from rules that combine words,but from the specification or instantiation of syntactic schemata or configurations,often expressing some kind of semantic content independently of the specific words that appear in them.This approach is essentially equivalent to a system of phrase structure rules combined with a noncompositional semantic theory,since grammatical formalisms based on rewriting rules are generally equivalent in power to those based on substitution into schemata.
So,in this type of approach,instead of being derived from the application of a number of phrase structure rules,the sentence "colorless green ideas sleep furiously" would be generated by filling the words into the slots of a schema having the following structure:
(NP(ADJ N) VP(V) AP(ADV))
And which would express the following conceptual content
X DOES Y IN THE MANNER OF Z
Though they are noncompositional,such models are monotonic.This approach is highly developed within Construction grammar,and has had some influence in Head-Driven Phrase Structure Grammar and Lexical functional grammar.

1. 引言
从50年代的机器翻译和人工智能研究算起，NLP（Natural
Language Processing，自然语言处理）已有长达半个世纪的历史。 在
这个进程中，学术界曾提出许多重要的理论和方法，取得了丰富的成果
。笔者认为，近二十年在这一领域中堪称里程碑式的贡献有如下三个：
（1）复杂特征集和合一语法；（2）语言学研究中的词汇主义；（...