12. The question and answer server according to claim 11 , further comprising a knowledge base, saving reasoning knowledge, and wherein the reasoning engine unit generates the natural language response according to the natural language understanding result, the language characteristics of the pet master, or the reasoning knowledge.
11. A question and answer server, comprising: a processor coupled to a memory storing instructions for execution by the processor; a sentence understanding engine module, when the instructions are executed by the processor processing natural language understanding on a natural language sentence received by the question and answer server, causing the question and answer server to send a natural language understanding result respectively to a learning engine unit and a reasoning engine unit, and causing the question and answer server to send a natural language response generated by the reasoning engine unit; the learning engine module, when the instructions are executed by the processor, obtaining language characteristics of a pet master according to a natural language understanding result, and save the language characteristics into a pet master language information base, wherein the language characteristics of the pet master include response habits commonly used by a user for responding to a certain natural language; and the reasoning engine module generating the natural language response according to the natural language understanding result and the saved language characteristics of the pet master; and the pet master language information base storing the language characteristics of the pet master, the learning engine unit, when the instructions are executed by the processor, further adjusting the language characteristics of the pet master according to the natural language understanding result, history chatting records of the pet master, or the saved language characteristics of the pet master, and saving the adjusted language characteristics into the pet master language information base.