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第1段
1 .<-NARRATOR:->Now listen to part of a lecture on the topic you just read about.
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第2段
1 .<-FEMALE PROFESSOR:->None of the three theories presented in the reading passage are very convincing.
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第3段
1 .First, the stone balls as hunting weapons.
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2 .Common Neolithic weapons such as arrowheads and hand axes generally show signs of wear.
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3 .So we should expect that if the stone balls had been used as weapons for hunting or fighting, they too would show signs of that use.
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4 .Many of the stone balls would be cracked or have pieces broken off.
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5 .However, the surfaces of the balls are generally very well preserved, showing little or no wear or damage.
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第4段
1 .Second, the carved stone balls may be remarkably uniform in size, but their masses vary too considerably to have been used as uniform weights.
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2 .This is because the stone balls were made of different types of stone, including sandstone, greenstone, and quartzite.
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3 .Each type of stone has a different density. Some types of stone are heavier than others.
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4 .Just as a handful of feathers weighs less than a handful of rocks, two balls of the same size are different weights depending on the type of stone they’re made of.
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5 .Therefore, the balls could not have been used as a primitive weighing system.
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第5段
1 .Third, it’s unlikely that the main purpose of the balls was as some kind of social marker.
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2 .A couple of facts are inconsistent with this theory.
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3 .For one thing, while some of the balls are carved with intricate patterns, many others have markings that are extremely simple—too simple to make the balls look like status symbols.
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4 .Furthermore, we know that in Neolithic Britain, when someone died, particularly a high-ranking person, they were usually buried with their possessions.
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5 .However, none of the carved stone balls have been actually found in tombs or graves.
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6 .That makes it unlikely that the balls were personal possessions that marked a person’s status within the community.
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