英语四级阅读部分答案及精解与点评4
Scientists have devised a way to determine roughly where a person has lived using a strand (缕) of hair, a technique that could help track the movements of criminal suspects or unidentified murder victims.
The method relies on measuring how chemical variations in drinking water show up in people’s hair.
“You’re what you eat and drink, and that’s recorded in your hair,” said Thure Cerling, a geologist at the University of Utah.
While U.S. diet is relatively identical, water supplies vary. The differences result from weather patterns. The chemical composition of rainfall changes slightly as rain 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 rain 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, scientist can construct 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 map 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 rain systems.
“It’s not good for pinpointing(精确定位),” Cerling said. “It’s good for eliminating many possibilities.”
Todd Park, a local detective, said the method has helped him learn more about an unidentified woman whose skeleton was found near Great Salt Lake.
The woman was 5 feet tall. Police recovered 26 bones, a T-shirt and several strands of hair.
When Park heard about the research, he gave the hair samples to the researchers. Chemical testing showed that over the two years before her death, she moved about every two months.
She stayed in the Northwest, although the test could not be more specific than somewhere between eastern Oregon and western Wyoming.
“It’s still a substantial area,” Park said. “But it narrows it way down for me.”
62. What is the scientists’ new discovery?
A) One’s hair growth has to do with the amount of water they drink. 无
B) A person’s hair may reveal where they have lived.
C) Hair analysis accurately identifies criminal suspects. 自、移
D) The chemical composition of hair varies from person to person. 无
答案：B。细节题，定位于第一段的下划线句子，B选项为其同意表达。A和D是明显的物种生有。C选项首先错在了accurately 这个词上，因为原文说的是roughly, 这里是自相矛盾。如果不认识这个副词的同学也没关系，还可以通过移花接木来排出。原文说的是track the movement of criminal suspects, 二unidentified是用来修饰victims的，所以C选项中的确定嫌犯的身份是移花接木。
总结：细节题，C选项稍有难度，不仔细看容易走眼，难度2颗星。
63. What does the author mean by “You’re what you eat and drink” (Line 1, Para. 3)?
A) Food and drink affect one’s personality development. 无
B) Food and drink preferences vary with individuals. 无
C) Food and drink leave traces in one’s body tissues.
D) Food and drink are indispensable to one’s existence. 无
答案：C。句子推断题，答案在定位点的前后段都可以得出，比较简单。即使有的同学不认识C选项中的body tissues是啥东西，但起码能看出来是身体的某个部位，而原文提到了头发，属于这个范畴，先保留备选。ABD中都含有明显的无中生有的信息，而且还不是生词，太好排除了。这样就选C
总结：句子推断题。根据上下文来选出答案并排除错选项。难度1颗星。
64. What is said about the rainfall in America’s West?
A) There is much more rainfall in California than in Utah. 无
B) The water it delivers becomes lighter when it moves inland.
C) Its chemical composition is less stable than in other areas. 自、推
D) It gathers more light isotopes as it moves eastward. 无
答案：B。B选项是原文下划线句子的同义表达，但下划线句子很难理解，所以很多网上其它机构都把这道题做错了。所以同学们做错了也正常，因为这些所谓的老师都能做错，何况是你们。原文这段范围的意思大致是“氢和氧这两种原子有同位素(同位素对于学理的同学要好理解一些，就是同是氢氧原子，有的原子量大一些，水就重一些，原子量小一些，水就轻一些，但这点原文并没有解释，所以加大了这里理解的难度)，最重的雨会首先降下来，结果导致了在太平洋洋面上形成的雨会在离海岸较近的加利福尼亚州先降下来(此时的雨比较重，是含大原子量同位素的水)，而轻一点的雨会等到更内陆的地方比如犹他州再降下来。经过我的解释，现在你们应该理解为什么选B了吧，确实有点难。而A选项是错的，我相信当时很多同学会选，很多网上的答案也把这道题选成了A。原文说的heavier rainfall很容被误解成事more rainfall，但这里不是，heavier 指的就是雨水的分子量重，而不是雨多。A的干扰性很大。C错的比较明显，因为原文说了说的氢氧原子是稳定的，而且也并没有吧这里的水的稳定性和别的地区作比较，属于自相矛盾或者推断过度都可以。D说的也是原文压根没提到的事，无中生有。
总结：此题为隐性推断题，而且信号词的America’s West在原文中没有，相当于原文的加州和犹他州，有点难，不过仍可以通过rainfall和“题文同序原则”找到定位点。定位之后理解又有难度，因为原文说的确实不是很明白，而且A的干扰性很大。此题很难，应该是本次四级考试中最难的一道题，此题难度5颗星，只有真正基础好的同学加上我上课讲的技巧才能答对。
65. What did Cerling’s team produce in their research?
A) A map showing the regional differences of tap water.
B) A collection of hair samples from various barber shops. 答
C) A method to measure the amount of water in human hair. 无
D) A chart illustrating the movement of the rain system. 移、无
答案：A。细节题，答案为范围段第一句的同义表达。B选项为范围内内容，但是答非所问，因为他们是用那个这些头发来验证这张地图(上过我课的同学应该记得在我第二节课的第一篇文章2001.6月讲英国南海岸房屋被海水侵蚀的时候，那篇文章里也出现过地图这个考点，有兴趣的同学可以回顾一下)，而并不是Cerling团队的产物。C是无中生有，这个amount of water已经是第二次作为干扰项出现了，第一次是第一道题的A选项中。D选项在范围只能没有，无中生有，或者有多读一点的同学可以当作是移花接木来排除掉。因为原文说的是这个地图中的regions是按照降雨的形成来划分的，而这个地图本身并不是为降雨形成所设计的。
总结：细节题，但D选项有一定干扰性，一些所谓的老师和网上参考答案也把这道题的答案给成了D。难度4颗星。少数同学能做对。
66. What is the practical value of Cerling’s research?
A) It helps analyze the quality of water in different regions. 无
B) It helps the police determine where a crime is committed. 无
C) It helps the police narrow down possibilities in detective work.
D) It helps identify the drinking habits of the person under investigation. 无
答案：C。简单的隐形推断题，C是原文划线两句话的组合。Detective这个词说明了是帮助了警察。ABD这三个选项都含有明显的无中生有的信息。文章其实读到我画横线的句子就已经能做出来了，我当时就最后的好几段都没读，选出了C，还是很明显的。
总结：利用“题文同序原则”定位。上过我课的同学这回知道“边读文章边做题，最后一起做难题”这种方法的好处了吧，可以帮助你节省时间，后面的都不用读了，错选项也更容易排除了。此题难度2颗星。大部分同学都能做对。
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