英语专四阅读理解练习（二十九）附答案解析

2015-02-12 10:32:27来源：网络

英语专四阅读理解练习（二十九）附答案解析

　　英语专四阅读提分的技巧来源于多做练习，不仅是为了高质快速选择答案正确，更重要的是希望同学们能从阅读理解练习中分析文章的布局安排，作者的意图，换位思考自己在专四写作中会如何运用。希望能对考生们有所帮助。

　　A controversy erupted in the scientific communityin early 1998 over the use of DNA (deoxyribonucleicacid ) fingerprinting in criminal investigations. DNAfingerprinting was introduced in 1987 as a method toidentify individuals based on a pattern seen in theirDNA, the molecule of which genes are made. DNA ispresent in every cell of the body except red blood cells. DNA fingerprinting has been usedsuccessfully in various ways, such as to determine paternity where it is not clear who thefather of a particular child is. However, it is in the area of criminal investigations that DNAfingerprinting has potentially powerful and controversial uses.

　　DNA fingerprinting and other DNA analysis techniques have revolutionized criminalinvestigations by giving investigators powerful new tools in the attempt to trove guilt, not justestablish innocence. When used in criminal investigations, a DNA fingerprint pattern from asuspect is compared with a DNA fingerprint pattern obtained from such material as hairs orblood found at the scene of a crime. A match between the two DNA samples can be used asevidence to convict a suspect.

　　The controversy in 1998 stemmed form a report published in December 1991 by populationgeneticists Richard C. Lewontin of Harvard University in Cambridge, Mass., and Daniel L. Hartlcalled into question the methods to calculate how likely it is that a match between two DNAfingerprints might occur by chance alone. In particular, they argued that the current methodcannot properly determine the likelihood that two DNA samples will match because they camefrom the same individual rather than simply from two different individuals who are members ofthe same ethnic group. Lewontin and Hartl called for better surveys of DNA patterns methodsare adequate.

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

　　1.Before DNA fingerprinting is used, suspects____.

　　A.would have to leave their fingerprints for further investigations

　　B.would have to submit evidence for their innocence

　　C.could easily escape conviction of guilt

　　D.cold be convicted of guilt as well

　　2.DNA fingerprinting can be unreliable when ____.

　　A.the methods used for blood- cell calculation are not accurate

　　B.two different individuals of the same ethnic group may have the same DNA fingerprintingpattern

　　C.a match is by chance left with fingerprints that happen to belong to two different individuals

　　D.two different individuals leave two DNA samples.

　　3.To geneticists like Lewontin and Hartl, the current method ____.

　　A.is not so convincing as to exclude the likelihood that two DNA samples can never comefrom two individuals

　　B.is arguable because two individuals of the same ethnic group are likely to have the same DNApattern.

　　C.Is not based on adequate scientific theory of genetics

　　D.Is theoretically contradictory to what they have been studying

　　4.The attitude of the Federal Bereau of Investigation shows that ____.

　　A.enough data are yet to be collected form various ethnic groups to confirm the unlikelihood oftwo DNA samples coming from two individual members

　　B.enough data of DNA samples should be collected to confirm that only DNA samples form thesame person can match

　　C.enough data are yet to be collected from various ethnic groups to determine the likelihoodof two different DNA samples coming form the same person

　　D.additional samples from various ethnic groups should be collected to determine that twoDNA samples are unlikely to come from the same person

　　5.National Academy of Sciences holds the stance that ____.

　　A.DNA testing should be systematized

　　B.Only authorized laboratories can conduct DNA testing

　　C.The academy only is authorized to work out standards for testing

　　D.The academy has the right to accredit laboratories for DNA testing

　　答案：CBABB

　　词汇讲解

　　1. erupt 爆发

　　An active volcano may erupt at any time.

　　活火山随时可能喷发。

　　It's many years since Mount Vesuvius last erupted.