Multi-agent Systems (MAS) are systems in which many intelligent agents interact with each other to accomplish a common goal, e.g. solving a complicated problem in a distributed environment. Domain specific knowledge can no longer solely support reasoning in MAS, whereas common sense knowledge becomes more critical to the reasoning quality, especially when e-Commerce has become more popular and more merchants are getting excited to the worldwide market. Incorporating common sense knowledge to the MAS is on edge. However, the use of common sense knowledge induces implementation dilemmas. For example, OpenCyc is not only a common sense knowledge base, but also has its own inference engine. Developers have to determine whether to use the existing inference engine or to use the one that OpenCyc provided. In this paper, four approaches to incorporate common sense knowledge to MAS are proposed and evaluated, and we finally advocate our favorite.