【正确答案】Knowledge and Diploma
   People usually connect knowledge with diploma. When you have learned a certain amount of knowledge in a school or a university, you can get a diploma. A diploma is a ruler to measure whether a person is qualified after studying for a period of time.
   It doesn't mean, however, that a person who has rich knowledge undoubtedly owns a diploma since a person can get knowledge by self-studying or in practice. Consequently, a diploma can not be constantly used to measure a person's ability for a certain job.
   Meanwhile, we cannot take it for granted that a person with a diploma is knowledgeable. It has been revealed that some people make false diplomas, while some others buy diplomas. By so doing, they are cheating not only the society but the buyers themselves as well. In order to make diplomas represent one's actual knowledge, the government should make laws to prevent the spreading of cheating.