Through practice on the one hand deepens the student to the book knowledge understanding and the study on the other hand enhances them to analyze the question in under the theory knowledge instruction to solve the question virtual rating .

通过实践，一方面加深学生对书本知识的理解和学习，另一方面提高他们在理论知识的指导下分析问题解决问题的 实际 能力。

Compared with history rating matrix virtual nearest neighbors ' rating matrix has small scale and contains the most useful information .

和历史评价矩阵相比， 虚拟最近邻 评价矩阵不但规模比较小，而且包含了 用户维上和项目维上对目标 评价最有价值的信息。