C Recently scientists have worked out a way to judge roughly where a person has lived using strands(缕) of hair, a technique that could help track the movements of criminal suspects or unidentified bodies . The method depends on measuring how chemical variations in drinking water show up in people’s hair. While U.S diet is relatively identical, water supplies vary. The differences result from weather patterns. The chemical composition of rainfall changes slightly as clouds move. Most hydrogen and oxygen atoms in water are stable , but traces of both elements are also present as heavier isotopes (同位素) . The heaviest raid（列阵）falls first. As a result, storms that form over the Pacific deliver heavier water to California than to Utah. Similar patterns exist throughout the U.S. By measuring the proportion of heavier hydrogen and oxygen isotopes along a strand of hair, scientists can establish a geographic timeline. Each inch of hair corresponds to about two months. Cerling’s team collected tap water samples from 600 cities and constructed a frame of the regional differences. They checked the accuracy of the map by testing 200 hair samples collected from 65 barber shops. They were able to accurately place the hair samples in broad regions roughly corresponding to the movement of raid systems. “It’s not good for pinpointing (精确定位),” he said. “It’s good for ruling out many possibilities.” 64. What can we learn from the passage about the latest discovery? A. One’s hair growth has to do with the amount of water they drink. B. A person’s hair may reveal where they have lived. C. Hair analysis identifies criminal suspects accurately. D. The chemical composition of hair varies from person to person. 65. What does the underlined word “identical” in paragraph 3 probably mean? A. similar B. fantastic C. beneficial D. healthy 66. What is the practical value of Cerling’s research? A. It helps analyze the quality of water in different regions. B. It helps the police determine where a crime is committed. C. It helps the police narrow down possibilities in detective work. D. It helps identify the drinking habits of the person under investigation. |