translation.en: They gave up the ability to make stone tools and fishing equipment and clothing because the population of about 4,000 people was simply not large enough to maintain the specialized skills necessary to keep the technology they had.
translation.zh: 他们放弃了生产骨制品， 钓鱼工具和制衣技能， 缘于四千人口 不是足够庞大 到需要专业分工技能， 才能维护他们拥有的科技。