听力原文： Back in those primitive times it was unnecessary to have a special form. of exchange value for everything, like a price. In those times the only things that were really valuable were the skills to survive. But as society became more complex, people depended more on others who were living far away then it became important for people to develop some method for exchanging value without having to exchange the actual goods. This need to develop a method for exchanging value was what led to the use of money. Money was a means of exchanging value without having to actually exchange the specific things you wanted. Before the use of money, people had to trade things with each other, and it was usually very difficult to decide what everything was worth in relation to each other. If you had three animals skins and your friend had two pots of dried beans, how did you know how many skins were equivalent to a pot of beans if they didn't have a price? With the introduction of money, all things could begin to have a common value that everybody could know about. This led to a standardized set of values among people. As the power of money increased, values that were different from the majority were no longer recognized. The value of something in terms of money became the ultimate value. In order for money to function, the whole society has to agree on the same values. (30)