Meandros de gramática española: confluencias y diferencias entre oración y sintagma verbal
This paper affirms that the subject-predicate relationship is characteristic of the verb phrase, and not of the sentence. The subject is a syntactic function that is carried out within the verb phrase not outside it. If the sentence is defined as the sequence which includes the above-mentioned relationship, the concept of sentence would be redundant. However, there are strong differences between the two. The author of this paper argues that the sentence is a paradigmatic unit, as opposed to the verb phrase which is a category of the syntagmatic unit, the phrase. Furthermore, the sentence belongs to the declarative level of the textual part of grammar in contrast to the phrase (including the verb phrase) that belongs to the syntactic part of grammar. The concepts of sentence and phrase are thus both necessary but they do not converge.
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