Scientists have known since 1952 that DNA is the basic stuff of heredity. They’ve known its chemical structure since 1953. They know that human DNA acts like a biological computer program some 3 billion bits long that spells out the instructions for making proteins， the basic building blocks of life.

But everything the genetic engineers have accomplished during the past half-century is just a preamble to the work that Collins and Anderson and legions of colleagues are doing now. Collins leads the Human Genome Project， a 15-year effort to draw the first detailed map of every nook and cranny and gene in human DNA. Anderson， who pioneered the first successful human gene-therapy operations， is leading the campaign to put information about DNA to use as quickly as possible in the treatment and prevention of human diseases.

What they and other researchers are plotting is nothing less than a biomedical revolution. Like Silicon Valley pirates reverse-engineering a computer chip to steal a competitor’s secrets， genetic engineers are decoding life’s molecular secrets and trying to use that knowledge to reverse the natural course of disease. DNA in their hands has become both a blueprint and a drug， a pharmacological substance of extraordinary potency that can treat not just symptoms or the diseases that cause them but also the imperfections in DNA that make people susceptible to a disease.

And that’s just the beginning. For all the fevered work being done， however， science is still far away from the Brave New World vision of engineering a perfect human—or even a perfect tomato. Much more research is needed before gene therapy becomes commonplace， and many diseases will take decades to conquer， if they can be conquered at all.

In the short run， the most practical way to use the new technology will be in genetic screening. Doctors will be able to detect all sorts of flaws in DNA long before they can be fixed. In some cases the knowledge may lead to treatments that delay the onset of the disease or soften its effects. Someone with a genetic predisposition to heart disease， for example， could follow a low-fat diet. And if scientists determine that a vital protein is missing because the gene that was supposed to make it is defective， they might be able to give the patient an artificial version of the protein. But in other instances， almost nothing can be done to stop the ravages brought on by genetic mutations. (409 words)

1. It can be inferred from the text that Collins and Anderson and legions of colleagues _____.

[A] know that human DNA acts like a biological computer program

[B] have found the basic building blocks of life

[C] have accomplished some genetic discovery during the past half-century

[D] are making a breakthrough in DNA

2. Collins and Anderson are cited in the text to indicate all the following EXCEPT that ______.

[A] time-consuming effort is needed to accomplish the detailed map of in human DNA

[B] human gene-therapy operations may be applied to the patients

[C] gene-therapy now is already generally used to the treatment and prevention of human diseases

[D] information about DNA may be used in the treatment and prevention of human diseases

3. The word “pirate” (line 2， paragraph 3) means______.

[A] one who robs at sea or plunders the land from the sea

[B] one who makes use of or reproduces the work of another without authorization

[C] to take (something) by piracy

[D] to make use of or reproduce (another’s work) without authorization

4. We can draw a conclusion from the text that_____.

[A] engineering a perfect human is not feasible for the time being

[B] it‘s impossible for scientists to engineer a perfect tomato

[C] many diseases will never be conquered by human beings

[D] doctors will be able to cure all sorts of flaws in DNA in the long run

5. The best title for the text may be ______.

[A] DNA and Heredity

[B] The Genetic Revolution

[C] A Biomedical Revolution

[D] How to Apply Genetic Technology

　　词汇注释

stuff 物质

preamble 开端

nook and cranny 排列

potency 力量

susceptible 易受感染的

predisposition 易患病的体质

　　难句讲解

1. They know that human DNA acts like a biological computer program some 3 billion bits long that spells out the instructions for making proteins， the basic building blocks of life.

[简析] 本句话的主干是“They know that…”。they 指的是前面句子中提到的scientists;第一个引导的是宾语从句，some 3 billion bits long修饰computer program，第二个that也修饰computer program;the basic building blocks of life是在解释proteins.

2. Anderson， who pioneered the first successful human gene-therapy operations， is leading the campaign to put information about DNA to use as quickly as possible in the treatment and prevention of human diseases.

[简析] 本句话的主干是“Anderson is leading the campaign…”。Who引导的非限定性定语从句，修饰Anderson;to put information…短语修饰campaign，其中的to use…作目的状语。

3. DNA in their hands has become both a blueprint and a drug， a pharmacological substance of extraordinary potency that can treat not just symptoms or the diseases that cause them but also the imperfections in DNA that make people susceptible to a disease.

[简析] 本句话的主干是“DNA has become both a blueprint and a drug”。in their hands修饰DNA;a pharmacological substance…是在解释前面的drug，其中的第一个that 引导的定语从句修饰pharmacological substance;第二个that引导的定语从句修饰imperfections.

4. And if scientists determine that a vital protein is missing because the gene that was supposed to make it is defective， they might be able to give the patient an artificial version of the protein.

[简析] 本句话的主干是“…they might be able to give the patient an artificial version of the protein”。If引导的是条件状语从句，其中的第一个that引导的是宾语从句，because引导的时原因状语从句;第二个that引导的定语从句修饰gene.

　　答案与解析

1. D 推论题。本题的问题是“根据本文，可以推知：柯林斯、安德森以及他们的众多同事”。题干中的“Collins and Anderson and legions of colleagues”出自文章第二段第一句话中，表明本题与第二段有关。第二段提到，柯林斯领导了“人类基因工程”研究项目，而安德森首创了人类第一次成功的基因治疗手术，并且正在领导一项有关DNA的研究活动;第三段接着介绍了他们掌握的DNA的作用。由此可知，这些研究人员对DNA的研究正在取得进步。[D]“正在取得DNA领域的突破”是对文中相关信息的概括，为正确答案。[A]“知道人类的DNA的作用就像一个生物学计算机程序”和[C]“在过去半个世纪里完成了一些基因发现”是第一段中提到的以前科学家的成果，不是柯林斯、安德森以及他们的同事的成果;[B]“发现了生命的基本构造元素”是针对文中“spells out the instructions for making proteins，the basic building blocks of life”这句话设置的干扰项。生命的基本构造元素是蛋白质，但这并不是这些研究人员发现的，所以[B]不对。

2. C 结构题。本题的问题是“文中引用柯林斯和安德森是为了表示下面各项，除了”。题干中的“Collins and Anderson”出自文章第二段第一句话中，表明本题与第二段有关。第二段提到这两人时指出，柯林斯领导的研究项目历时15年，旨在绘制第一张人类DNA基因排列详细图表，而安德森首创了人类第一次成功的基因治疗手术，他正在领导的研究准备把有关DNA的信息尽可能迅速地用于治疗并预防人类的疾病;第三段提到，他们掌握的DNA可以治疗症状或者导致症状的疾病。这说明，[A]“为了完成人类DNA的详细基因图，需要付出很大的努力”、[B]“人类基因疗法手术可能被用来治疗患者一和[D]”有关DNA的信息可能被用来治疗并预防人类的疾病“体现了提到这两人的目的。[C]”如今，基因疗法普遍用于治疗并预防人类的疾病“明显与第四段第三句话的意思不符。

3. B 词义题。本题的问题是“单词‘pirate’(第三段第二行)最可能的意思是”。第三段提到该词时是说，这些人反向设计一种电脑芯片去窃取竞争对手的秘密。根据“Sili.”Vailev“可知，[A]”一个在海上抢劫或者从海上抢劫陆地的人“不对;本句话是把该词与genetic，engineers进行比较，说明该词应该是指_人，所以，[C]”通过盗版获得(某物)“和 [D]”没有得到授权利用或者复制(他人工作)“不对。只有[B]”一个没有得到授权利用或者复制他人工作的人“符合文意。

4. A 归纳题。本题的问题是“根据本文，我们可以得出结论”。文章前面三段介绍了遗传工程师取得的成就，第四段指出，科学离实现设定一个完美人类的梦想还很遥远，孝基因疗法普遍之前，人们还需要进行更多的研究。这说明，目前的科学还不能设定一个完美人类。[A]“设定完美的人目前还不可行”是对文中相关信息的改写，为正确答案。文中是说科学离设定完美土豆的梦想很遥远，但并没有说不可能，所以[B]“科学家要想设定一个完美的土豆是不可能的”与文意不符;[C]“许多疾病永远也不会被人类征服”是针对第四段最后一句话设置的干扰项，文中是说“许多疾病也需要花费几十年的时间去征服，如果它们可以被人类完全征服的话”，并不能说人类不能征服许多疾病，所以[C]不对;文中只是说“医生可以检测DNA中的所有缺陷”，并没有说可以治愈，所以[D] “从长远来看，医生可能治愈DNA中的所有缺陷”不对。

5. B 主旨题。本题的问题是“本文的最佳标题可能是”。文章前面几段介绍了遗尊工程师取得的成就，后面两段介绍了科学家在将基因疗法用于治疗疾病方面面临的问题。这说明，本文主要是介绍基因领域的研究。[B]“基因革命”是对本文的恰当概括，可以表达本文的主题，为正确答案。DNA是科学家研究的具体内容，不是本文探讨的主题，所以[A]“DNA与遗传”不能表达本文的主题;[C]“一场生物医学革命”概念太广，不准确;有关新技术的利用是最后一段的内容，比较片面，所以[D]“如何应用基因技术”不能表达本文的主题。