关键词: 句群, 领域, 概念层次网络理论, 信息抽取, 文本分类

Abstract: Sentence group is a processing unit between sentence and paragraph.It is composed of three elements：domain，situation and background，but domain is the most essential.Once the domain of sentence group is obtained，the situation will be exposed.This is very important for information retrieval and text classification.The symbols of domain are contained in some words.The domain of a sentence can be analyzed by the semantic role，position and frequency of words.Sentence group and its domain can be extracted by combining sentences with the same or similar domain.The experiment shows that the four kinds of relationships between two domains are processed well.However，the process of dynamic words and the recognition of complex domain should be improved.

Key words: sentence group, domain, the theory of Hierarchical Network of Concepts, information extraction, text classification