托福听力背景知识：历史年代测定。为了备考托福听力，一些考题中经常出现的背景资料必不可少，尤其是科普知识，如果不了解就会让 托福听力考试更加陌生。以下是有关考古中历史年限的测定方面的知识，同学们来了解一下吧。　　

　　If there is one fundamental issue on which most archaeologists can generally agree, it is the importance of chronology in studying the past. Although one of the most important contributions that archaeology can make is the study of cultures over long time spans, control of the time dimension is crucial in almost all kinds of archaeological research. In studying the archaeological record, the archaeologist needs to differentiate those materials that are contemporary and those that reflect the passage of time. Given the importance of establishing the temporal relationships of archaeological remains, it is not surprising that until the introduction of dating techniques from the physical sciences (e.g., chemistry and nuclear physics), issues of chronology dominated archaeology. Archaeologists can now access a wide variety of techniques to estimate the age of archaeological remains, and can now turn their attention to issues other than chronology.