Abstract: Question Answering(QA) system is a system that puts the question and the answer into a database and organizes them. This system can answer students’ questions automatically by a technology named semantic understanding used for understanding natural language. The design and implementation of QA System are presented. This system adopts twosides mostly matched method, intellectual question match pattern and semantic analyze means which are based on dependent parsing tree for the question analyzing. A great deal of corrective rate and answering callback rate in our test show that this system is a new good system.

Key words: semantic dependence , question pattern match, word segmentation