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.