关键词: 问答系统, 问题分类, 特征选择, 依存关系, 上位词

Abstract: Question classification is a very important sub-module of question answering system，and the key lies in the feature selection.This paper proposes a new feature selection method based on syntactic and semantic information，using the question word，the main verb of the question，the dependency structure，the main noun and the top hypernym of the noun as features for classification.Evaluate the effect of feature selection using KNN and Na?觙ve Bayes classifiers，and attain an expected result.In the predefined question taxonomy，the classification accurate reaches 82.2% and 83.7% respectively.It is better than the method using bag-of-words features.

Key words: question answering system, question classification, feature selection, dependency structure, hypernym