（）的前提是被计量的量值必须具有能与国家计量基准直至国际计量基准相联系的特性，也就是溯源性。
参考答案：量值准确一致
Many people in Haiti died from the earthquake because they didn't have _____ to immediate rescue. [ ]
A. access
B. admission
C. approach
D. attention
如果甲产品和乙产品的需求交叉弹性系数是负数，则说明甲产品和乙产品______。
A．无关 B．是替代品C．是互补品 D．是缺乏价格弹性的
