【正确答案】 B

【答案解析】[听力原文] W: Dr. Thomas? This is Keet Bradley from Daily News. I'd like to ask you some questions about the new official standard weight that you purchased. M: I'd be happy to help you. What would you like to know? W: First of all, how was the standard weight used? M: Well, the people in our department use it to check the scales all over the country. The department of weights and measures, we are a government agency. It's our responsibility to see that all the scales measure a kilogram accurately so this is the way we use to adjust the scales. W: How did you check the scales before? M: We have an old standard weight that we used to use. It had to be replaced because it was imprecise. You see it was made of poor quality metal that was too porous. It absorbed too much moisture. W: Oh. So when the weather was humid it weighed more and when it was dry it weighed less. M: Exactly. And the variation can affect the standards of the whole country. So our department had the new weight made out of higher quality metal. W: How much did it cost? M: About 45 thousand dollars. W: 45, 000 dollars? For one kilogram weight? That's more expensive than gold. Is it really worth that much? M: I'm sure it is. Industries depend on our government agency to monitor the accuracy of scales so that when they buy and sell their products there is one standard. Think of the drug industry, for example, those companies rely on high accuracy scales to manufacture and package medicine. What is the conversation mainly about? 对话开始主持人便向Dr. Thomas提出是否可以谈谈官方标准重量砝码，接下来对标准砝码的使用、与过去砝码的比较和现用标准砝码的价格进行讨论，可知本篇对话主要话题是标准砝码，故选B。

【正确答案】 A

【答案解析】[听力原文] What was the weight used for? 主持人问Dr. Thomas这个标准砝码的用途是什么时，Dr. Thomas回答说他们部门里的人用它检测全国的天平，并在全国范围内统一标准，故选A。

【正确答案】 C

【答案解析】[听力原文] Why was the old standard weight replaced? 主持人问Dr. Thomas以前是如何检测天平的，Dr. Thomas回答说过去使用的老式砝码不得不换掉了，因为过去的砝码是用多孔的劣质金属所制，吸收了大量的湿气而导致测量不准，故选C。

【正确答案】 D

【答案解析】[听力原文] What is Dr. Thomas's attitude towards the cost of the new weight? 当主持人得知标准砝码价格是45, 000美元时十分吃惊，觉得它比金子还贵，于是询问Dr. Thomas标准砝码是否值这个价，但Dr. Thomas非常肯定地说所有的实业公司都依赖政府机关来监控天平的准确性，因此它们在购买和销售产品时，得有一个标准检测重量，并以医药行业为例来说明，所以Dr. Thomas认为这个价格是合理的，故选D。