Question 13 is based on the passage you have just heard.

听力原文

    Setting the office air-conditioning at about 22 degrees Celsius has become standard practice across the world. Numerous guidebooks across the world on heating, ventilation and air-conditioning claim office performance peaks at 22 degrees. Many people indeed find relief from soaring summer temperatures in air-conditioned offices, (12) [but recent studies have challenged the accepted wisdom that a cool office is more productive: the reality is more complex.] 

    Researchers conducted a review of all studies relating to air-conditioning and productivity. They found that 22 degrees was probably a little chilly, even at the height of summer. (13) [For a person dressed in typical summer clothing, an optimal range would be between 23 and 26 degrees.] And people can even tolerate temperatures beyond this “comfort zone”, as long as they can adjust their clothing and expectations. (14) [In fact, even on very hot days, it makes sense to turn the air-conditioning up.] People often chase just one “optimum” temperature. And this is understandable when people feel hot, (14) [but there is a range of at least 3 to 4 degrees which does not have any adverse impact.] 

    Another issue related to this is that people can become psychologically dependent on air-conditioning. (15) [If they are used to the environment which is air-conditioned, they tend to prefer lower temperatures.] But the studies found that almost all humans became accustomed to the new temperature. It was only at the “extreme” ends of the temperature range where people’s productivity suffered. This range was above 26 degrees and below 19 degrees.

13. What did researchers find from their review of all studies relating to air-conditioning and productivity?（研究人员通过回顾空调和工作效率的相关研究，得出了什么结论？）

解析：D。录音中间部分提到，23度到26度之间对穿正常夏装的人来说是最舒适的温度。D项与此内容相符，其中a range of temperatures对应录音中的between 23 and 26 degrees，to feel comfortable对应录音中的an optimal range，故D项为正确答案。

错项排除：录音中只是提到关于空调和工作效率的研究的一些回顾总结，并没有提到人们在什么情况下对自己的工作效率更满意，A项只是利用录音中出现的comfort zone、temperature和productivity进行细节拼凑，故排除。录音没有提到不同国家的人（People in different countries）承受温度的能力，故B项排除。录音中提到即使是在最热的时候，空调开到22度可能也有点冷，否定了22度是最佳温度这一传统观点，C项内容与录音相悖，故排除。