Question 21 is based on the recording you have just heard.

Recording Two

听力原文

        Ageing is a curious thing, and people’s desire to beat it and death has become an industry worth hundreds of billions of dollars. Despite the huge investment into research, ageing remains somewhat obscure, although there are certain things researchers do understand. They know that women tend to have longer lifespans, living on average six years longer than men. (19) [No one is really certain of the reason for this, although the speculation centers around the idea that women are more capable of surviving or handling disease than men.] For virtually every disease, the effects are greater on men than they are on women. Some suggest that women’s immune systems benefit from their tendency to prioritize and nurture social connections. But for me, this explanation is hardly convincing.

        Researchers also know, to an extent, what causes ageing. For 60 years, it was believed that cells would continue to divide forever. It was only uncovered in relatively recent times that older people’s cells divide a smaller number of times than younger people’s. Only cancer cells, in fact, are capable of dividing forever. (20) [Human cells have a limited reproductive ability.] To an extent, we can postpone the eventual stop of cells dividing through nutrition, exercise, good sleep and even relaxation techniques, but we cannot stop the ageing process.

       And researchers are yet to answer the ultimate question of ageing: why does the body ultimately fall to pieces? In the opinion of some of the world’s best scientific minds on the subject, part of the reason we don’t yet have an answer is because many researchers are looking in the wrong direction. (21) [Many public health policymakers believe that the resolution of age-associated disease will tell us something fundamental about the ageing process,] but, say some top scientists, “that’s completely erroneous.” They point to when the diseases of childhood were eliminated, but this did not provide any insight into childhood development. In the same way, the idea that the resolution of age-associated disease like heart disease and stroke will inform us about ageing is not based on sound science or logic. At best, if the major causes of death in developed countries were eliminated, this would only add a decade to average life expectancy. But while there is money available to be spent on it, the search to understand the secrets of ageing will be ongoing.

21. What do many public health policymakers believe?（许多公共卫生决策者相信什么？）

解析：D。录音中表示，许多公共卫生政策制定者认为，解决与年龄有关的疾病将告诉我们老龄化过程的一些基本情况，即他们认为解决与年龄有关的疾病将解开衰老之谜，D项中的resolution of age related disease是对录音中resolution of age-associated disease的同义替换，solve the mystery of ageing对应录音中的tell us something fundamental about the ageing process，故D项正确。

错项排除：录音中明确提到，我们无法阻止衰老过程（cannot stop the ageing process），A项与此内容相悖，故排除。B项的关键词Improved health care在录音中并未提及，故排除。C项利用录音中出现的heart disease、stroke和life expectancy进行拼凑，但这是录音中顶尖科学家（some top scientists）的观点，并非公共卫生决策者的观点，故C项排除。