第2题: [单项选择]Questions 22 to 25 are based on the conversation you have just heard. A. To check the accuracy of scales. B. To calculate the density of other metals. C. To observe changes in the atmosphere. D. To measure amounts of rainfall. 参考答案:A 答案解析:[听力原文] Q: What was the purpose of the standard weight [答案详解] 由对话中的check the scales all ov