15. The data search method according to claim 12 wherein the analyzing of the lexical meaning of the modifier executes syntactic and semantic analysis processing of the input question to extract the question focus and the modifier from the input question.
15. The data search method according to claim 12 wherein the analyzing of the lexical meaning of the modifier executes syntactic and semantic analysis processing of the input question to extract the question focus and the modifier from the input question. 16. The data search method according to claim 15 , wherein the analyzing of the lexical meaning of the modifier further extracts the question focus and a phrase portion containing a verb directly modifying the question focus from the input question using a case frame dictionary in the syntactic and semantic analysis processing of the input question.