阅读理解

In this section there are five reading passages followed by a total of 20 multiple-choice questions and 5 short answer questions. Please read the passages and then write your answers on the ANSWER SHEET.


TEXT D

A controversy erupted in the scientific community in early 1998 over the use of DNA (deoxyribonucleic acid) fingerprinting in criminal investigations. DNA fingerprinting was introduced in 1987 as a method to identify individuals based on a pattern seen in their DNA, the molecule of which genes are made. DNA is present in every cell of the body except red blood cells. DNA fingerprinting has been used successfully in various ways, such as to determine paternity where it is not clear who the father of a particular child is. However, it is in the area of criminal investigations that DNA fingerprinting has potentially powerful and controversial uses.

DNA fingerprinting and other DNA analysis techniques have revolutionized criminal investigations by giving investigators powerful new tools in the attempt to prove guilt, not just establish innocence. When used in criminal investigations, a DNA fingerprint pattern from a suspect is compared with a DNA fingerprint pattern obtained from such materials as hairs or blood found at the scene of a crime. A match between the two DNA samples can be used as evidence to convict a suspect.

The controversy in 1998 stemmed from a report published in December 1991 by population geneticists Richard C. Lewontin of Harvard University in Cambridge, Mass., and Daniel L. Hartl called into question the methods to calculate how likely it is that a match between two DNA fingerprints might occur by chance alone. In particular, they argued that the current method cannot properly determine the likelihood that two DNA samples will match because they came from the same individual rather than simply from two different individuals who are members of the same ethnic group.

In response to their criticisms, population geneticists Ranajit Chakraborty of the University of Texas in Dallas and Kenneth K. Kidd of Yale University in New Haven, Conn., argued that enough data are already available to show that the methods currently being used are adequate. In January 1998, however, the federal Bureau of Investigation and laboratories that conduct DNA tests announced that they would collect additional DNA samples from various ethnic groups in an attempt to resolve some of these questions. And, in April, a National Academy of Sciences called for strict standards and system of accreditation for DNA testing laboratories. 

单选题 Before DNA fingerprinting is used, suspects _____.
【正确答案】 C
【答案解析】第二段第一句提到DNA指纹分析为检察官们证明嫌犯有罪提供了新的工具， 可见， 在此之前， 嫌犯很容易逃脱指证。故选C。
单选题 DNA fingerprinting can be unreliable when _____.
【正确答案】 B
【答案解析】第三段最后一句提到DNA指纹分析的方法有时候无法辨别同族相同的DNA指纹， 在这种情况下DNA指纹分析法就不可靠。故选B。
单选题 To geneticists like Lewontin and Hartl, the current method _____.
【正确答案】 A
【答案解析】第三段最后一句提到Lewontin和Hartl认为DNA指纹分析的方法并不完全可靠， 因为其排除了两个相同DNA可能来自不同个体的可能性。故选A。
单选题 The attitude of the Federal Bureau of Investigation shows that _____.
【正确答案】 B
【答案解析】从文章最后一段可以看出联邦调查局希望收集更多DNA样本数据提高这种调查法的精确性而不能让样本与有着相似DNA的不同人相匹配。B项最符合题意。故选B。
单选题 National Academy of Sciences holds the stance that _____.
【正确答案】 B
【答案解析】文章最后一段最后一句提到“a National Academy of Sciences called for strict standards and system of accreditation for DNA testing laboratories.”国家科学院提倡对DNA测试实验室要有严格标准和认证系统。故选B。