题目原文：
Carved stone balls are a curious type of artifact found at a number of locations in Scotland. They date from the late Neolithic period, around 4,000 years ago. They are round in shape; they were carved from several types of stone; most are about 70 mm in diameter; and many are ornamented to some degree. Archaeologists do not agree about their purpose and meaning, but there are several theories.
One theory is that the carved stone balls were weapons used in hunting or fighting. Some of the stone balls have been found with holes in them, and many have grooves on the surface. It is possible that a cord was strung through the holes or laid in the grooves around the ball. Holding the stone ball at the end of the cord would have allowed a person to swing it around or throw it.
A second theory is that the carved stone balls were used as part of a primitive system of weights and measures. The fact that they are so nearly uniform in size—at 70 mm in diameter—suggests that the balls were interchangeable and represented some standard unit of measure. They could have been used as standard weights to measure quantities of grain or other food, or anything that needed to be measured by weight on a balance or scale for the purpose of trade.
A third theory is that the carved stone balls served a social purpose as opposed to a practical or utilitarian one. This view is supported by the fact that many stone balls have elaborate designs. The elaborate carving suggests that the stones may have marked the important social status of their owners.
题目音频：
学术写作：
教授：过度消费是否已经成为一个严重的问题？
Andrew: 是。
Claire: 不是。
Doctor Achebe: We’ve been discussing the idea that human well-being is not necessarily improved by ever-increasing production and consumption of goods and services. Some people argue that humans already consume too many goods, from clothing to electronics to food; they believe that excessive consumption has created serious problems for humanity and even the planet. Do you agree that excessive consumption–buying more than we truly need–has become a serious problem? Why or why not?
Andrew: I absolutely agree. We buy far more than we need, and that can’t continue indefinitely. For years people have used shopping as a form of recreation. The products bought on a whim are filling up landfills, and the energy expended producing the goods has created a global warming crisis. We should start gradually reducing consumption.
Claire: I disagree with the idea that over-consumption is a dramatic problem. I agree there is some over-consumption, but it happens mostly with wealthy people. I think in general almost everyone else already buys only what they need. In fact, many people around the world are not even able to obtain everything they need.
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