At 18, Ashanthi DeSilva of suburban Cleveland is a living symbol of one of the great intellectual achievements of the 20th century. Born with an extremely rare and usually fatal disorder that left her without a functioning immune system (the "bubble-boy disease," named after an earlier victim who was kept alive for years in a sterile plastic tent), she was treated beginning in 1990 with a revolutionary new therapy that sought to correct the defect at its very source, in the genes of her white blood cells. It worked. Although her last gene-therapy treatment was in 1992, she is completely healthy with normal immune function, according to one of the doctors who treated her, W. French Anderson of the University of Southern California. Researchers have long dreamed of treating diseases from hemophilia to cancer by replacing mutant genes with normal ones. And the dreaming may continue for decades more. "There will be a gene-based treatment for essentially every disease," Anderson says, "within 50 years."

　　It's not entirely clear why medicine has been so slow to build on Anderson's early success. The National Institutes of Health budget office estimates it will spend $432 million on gene-therapy research in 2005, and there is no shortage of promising leads. The therapeutic genes are usually delivered through viruses that don't cause human disease. "The virus is sort of like a Trojan horse," says Ronald Crystal of New York Presbyterian/Weill Cornell Medical College. "The cargo is the gene."

　　At the University of Pennsylvania's Abramson Cancer Center, immunologist Carl June recently treated HIV patients with a gene intended to help their cells resist the infection. At Cornell University, researchers are pursuing gene-based therapies for Parkinson's disease and a rare hereditary disorder that destroys children's brain cells. At Stanford University and the Children's Hospital of Philadelphia, researchers are trying to figure out how to help patients with hemophilia who today must inject themselves with expensive clotting drugs for life. Animal experiments have shown great promise.

　　But somehow, things get lost in the translation from laboratory to patient. In human trials of the hemophilia treatment, patients show a response at first, but it fades over time. And the field has still not recovered from the setback it suffered in 1999, when Jesse Gelsinger, an 18-year-old with a rare metabolic disorder, died after receiving an experimental gene therapy at the University of Pennsylvania. Some experts worry that the field will be tarnished further if the next people to benefit are not patients but athletes seeking an edge. This summer, researchers at the Salk Institute in San Diego said they had created a "marathon mouse" by implanting a gene that enhances running ability; already, officials at the World Anti-Doping Agency are preparing to test athletes for signs of "gene doping." But the principle is the same, whether you're trying to help a healthy runner run faster or allow a muscular-dystrophy patient to walk. "Everybody recognizes that gene therapy is a very good idea," says Crystal. "And eventually it's going to work."

1.The case of Ashanthi Desilva is mentioned in the text to ____________.
　　[A] show the promise of gene-therapy
　　[B] give an example of modern treatment for fatal diseases
　　[C] introduce the achievement of Anderson and his team
　　[D] explain how gene-based treatment works

2.Anderson’s early success has ________________.
　　[A] greatly speeded the development of medicine
　　[B] brought no immediate progress in the research of gene-therapy
　　[C] promised a cure to every disease
　　[D] made him a national hero

3.Which of the following is true according to the text?
　　[A] Ashanthi needs to receive gene-therapy treatment constantly.
　　[B] Despite the huge funding, gene researches have shown few promises.
　　[C] Therapeutic genes are carried by harmless viruses.
　　[D] Gene-doping is encouraged by world agencies to help athletes get better scores.

4.The word “tarnish” (line 5, paragraph 4) most probably means ____________.
　　[A] affect
　　[B] warn
　　[C] trouble
　　[D] stain

5.From the text we can see that the author seems ___________.
　　[A] optimistic
　　[B] pessimistic
　　[C] troubled
　　[D] uncertain

　　答案：A B C D A

　　篇章剖析：

　　本篇文章是说明文，主要说明基因疗法的前景，现状，遭遇的问题以及人们对待基因疗法的态度。文章第一段以上世纪90年代一次成功的基因治疗为例说明基因疗法的广阔前景。第二段介绍了基因疗法的现状和治疗机制。第三段介绍了目前用基因疗法治疗多种疾病的研究情况，第四段介绍了基因疗法遭遇的问题以及人们对基因疗法的态度。

　　词汇注释：

　　sterile: [5sterail] adj. 无细菌的；消毒的

　　gene-therapy 基因疗法

　　hemophilia：[7hi:mE5filiE] n. 血友病

　　mutant: [5mju:tEnt] n. 〈生〉突变型；突变体

　　therapeutic: [WerE5pju:tik] adj. 治病的；治疗术的；治疗学的

　　Trojan horse: (神话)特洛伊木马(特洛伊战争时希腊人做的木马, 希腊兵藏在木马腹中, 混入特洛伊城); [喻]内部的破坏集团

　　cargo: [5kB:^Eu] n. （船、飞机 所载的）货物

　　immunologist: [7imju5nClEdV ist] n. 免疫学家

　　Parkinson’s disease: 震颤(性)麻痹症；帕金森症

　　clot: [klCt] v. (使)凝结

　　metabolic: [7metE5bClik] adj. 代谢作用的, 新陈代谢的

　　tarnish: [5tB:niF] v. ，败坏；玷污；诽谤；中伤

　　edge: [edV] n. 优势

　　doping: [5dEupiN] n. 加添加剂

　　dystrophy: [5distrEfi] n. 〈医〉营养不良

　　难句突破：

　　Born with an extremely rare and usually fatal disorder that left her without a functioning immune system (the "bubble-boy disease," named after an earlier victim who was kept alive for years in a sterile plastic tent), she was treated beginning in 1990 with a revolutionary new therapy that sought to correct the defect at its very source, in the genes of her white blood cells.

　　主体句式：she was treated with a …therapy

　　结构分析：这是一个复杂长句。过去分词born引导了一个包含定语从句（that引导的定语从句，修饰disorder）和插入语（同样在其中含有带定语从句的分词短语）的原因状语，主句后面又跟了一个定语从句（that引导的用来修饰therapy的 从句）。

　　句子译文：她生来就患上了一种极为罕见而且通常致命的免疫系统不全症（即“气泡男孩症”，该病名得名于早期的一位在消过毒的塑料帐篷里生活多年的患者），从1990年开始，她就接受了一种全新的治疗方法，这种方法试图在源头，在她的白血球基因中治疗免疫缺陷。

　　题目分析：

　　1. 答案为A，属推理判断题。文章第一句话对用基因疗法治疗Ashanthi所患罕见疾病的成功给与了很高的评价，并在第一段末指出医生们对基因疗法寄予了极高的期望。由此可见，答案应该是A。

　　2. 答案为B，属事实细节题。文章第二段一开头就说：“It's not entirely clear why medicine has been so slow to build on Anderson's early success.”从时间上来