When select the expansion term for query term, we full use of the language component, the polysemy and ambiguity of natural language words, and consider the limited of context of semantics, and so on. 该方法在对查询选取扩展词时充分利用了语言成分以及自然语言词汇具有多义性和歧义性,并且考虑了上下文对语义的限定等因素。