A. And that variation can affect the standards of the whole countryB. Is it really worth that muchC. How did you check the scales beforeD. What would you like to knowInterviewer: Dr. Thomas? I'd like to ask you some questions about the new official standard weight that you purchased. Dr. Thomas: I'd be happy to help you.【D7】______?Interviewer: First of all, how was the standard weight used? Dr. Thomas: 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 used to adjust the scales. Interviewer:【D8】______? Dr. Thomas: 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 and absorbed too much moisture. Interviewer: So when the weather was humid it weighed more and when it was dry it weighed less. Dr. Thomas: Exactly.【D9】______. So our department had the new weight made out of higher quality metal.Interviewer: How much did it cost? Dr. Thomas: About 45, 000 dollars.Interviewer: 45,000 dollars? For one kilogram weight? That's more expensive than gold.【D10】______?Dr. Thomas: 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.
【答案解析】解析：Dr．Thomas说以前称重标准物是由劣质金属做的，容易吸收湿气。采访者由此判断when the weather was humid it weighed more and when it was dry it weighed less(天气潮湿的时候，就重一些，天气干燥的时候就轻一些)。Dr．Thomas表示赞成并总结这个变化会影响全国的标准。故A为正确答案。