The research of linguistics had been within the limit of morpheme, vocabulary, sentence and the meaning of sentence expression during a long period of time. The study above unit of sentences has been once considered as the problems in the fields of rhetoric and literature. 在相当长的一段时间内,语言学的研究范围局限在词素、词汇、句子以及词汇和句子表达的意义上,对句以上单位的研究被看作是修辞学、文学研究等领域的事。