I. Introduction
Recent years, more and more customers release reviews on the web after using products. The reviews contain a wealth of information, which can help manufacturer to improve products and help potential customers to make a decision on whether to buy the product [1]. The number of customer reviews of a popular product can be hundreds and the reviews are mostly expressed by natural language. If anyone wants to get the information from customer reviews, he must look through the reviews one by one. As a rising field of information extraction, product review mining can acquire information from customer reviews automatically and quickly, so it can help people get rid of the hard job.