1、国家公共英语五级（阅读理解）练习试卷 8及答案与解析 Part A Directions: Read the following texts and answer the questions which accompany them by choosing A, B, C or D. Mark your answers on ANSWER SHEET 1. 0 Tobaccos public image couldnt be more stained these days, given the war on cigarettes in the courts, federal and state
2、 governments, the medical establishment even in Doonesbury. But the tobacco plant is not an irredeemable never-do-well. Because its genetic makeup is fairly straightforward and well understood, scientists believe tobacco could turn out to be the perfect blotch factory for protein-based drags. By spl
3、icing human genes a technique developed in the early 1990s researchers have enabled tobacco plants to produce a number of drugs and vaccines and even human blood components. Within 10 years, researchers are hopeful that tobacco farmers might be raising millions of acres of biofactories rather than “
4、the killer weed“. The latest breakthrough in tobacco “pharming“ may bring such a vision one step closer to reality. Scientists at Monsanto Co. (MTC) reported in the March issue of Nature Biotechnology that they were able to genetically engineer tobacco plants to produce human growth hormone, otherwi
5、se known as somatotropin an extremely costly drug used to treat dwarfism. But the Monsanto discovery was more important for the press than the product. The scientists were able to induce the tobacco plants to manufacture the drug in an abundant piece of the plant cell known as a chloroplast, which i
6、s responsible for converting light into food. Other efforts to create drug-producing plants have altered plant nuclei instead far less numerous cell components. DNA Dilemma. “We were able to produce 300-fold more human somatotropin in the chloroplasts than in the nucleus,“ says Jeffrey M. Staub, man
7、ager of the Monsanto team that developed the technique. “As an optimistic scientist, I think it is very reasonable to believe, we will be able to produce commercial quantities of human proteins in the plants in the next couple of years.“ There has been notable progress with gene-spliced plants in th
8、e past two years. In 1998, British researchers reported that a human antibody grown in tobacco plants prevented one of the bacterial infections that led to tooth decay in human volunteers. And last August, the Energy Dept.s Pacific Northwest National Laboratory announced that its scientists had succ
9、essfully transplanted the necessary human genes into tobacco plants to produce human blood components. Even with plants, though, volume remain a problem. All plant cells contain subunits called organelles, two of which are the nucleus and the chloroplast. Gene splicing to date has focused on alterin
10、g the nucleus essentially the brain of the cell, because it controls all of the plants activities. But drug production was limited, since there is only one nucleus per cell. Moreover, the genetic alteration is transmitted to the plants pollen, making it difficult to control the spread of the reengin
11、eered plants. Chloroplasts, however, are abundant, and they do not spread their genetic changes to any other cells in the plant. 1 What does the passage mainly discuss? （ A） Tobaccos public image will never change. （ B） Chloroplast will make tobacco change its social role. （ C） Nuclei is more import
12、ant than chloroplast. （ D） DNA Dilemma is very optimistic. 2 The word “breakthrough“ in the 1st sentence of the 2nd paragraph is closest in meaning to _. （ A） breakaway （ B） breakdown （ C） a sudden important development （ D） the illegal entering of a building 3 Which of the following statements is N
13、OT true? （ A） Somatotropin is used to treat dwarfism. （ B） Nuclei is far less numerous component. （ C） Chloroplast is responsible for converting light into food. （ D） Somatotropin is not of hormone. 4 Based on the information of the last paragraph, which of the following is true? （ A） The number of
14、chloroplasts is limited. （ B） Chloroplasts do not spread their genetic changes to other cells in the plant. （ C） Nucleus and chloroplast are all the subunits that plant cells contain. （ D） Gene splicing date has focused on altering all the organelles. 5 It can be inferred from the text that _. （ A）
15、tobacco may finally have a chance to transcend its societal role as a cancer-causing blight （ B） tobacco should be prohibited to plant （ C） cigarettes will be accepted by scientists （ D） tobacco plants cannot be used to produce hormone Part B Directions: In the following article some paragraphs have
16、 been removed. For Questions 66-70, choose the most suitable paragraph from the list A-F to fit into each of the numbered gaps. There is one paragraph which does not fit in any of the gaps. Mark your answers on ANSWER SHEET 1. 5 Opinion polls repeatedly tell us that the only thing Americans worry ab
17、out more than the environment is their health. This is entirely understandable, for health is obviously preferable to illness. What makes todays preoccupation with health slightly surprising is that Americans are far healthier now than they have ever been. 16._ Nonetheless, health and the various th
18、reats to it remains everyones permanent concern. After all, more than half of us will die from either heart disease or cancer, if current trends continue. 17._ For instance, AIDS if you get it will probably be fatal after a number of years. Cancer induced by smoking or exposure to radiation, on the
19、other hand, may take 20 to 30 years before its catastrophic effects show up. In making choices about health risks, therefore, it is important to bear in mind the likely time lag between taking a risk and suffering its consequences. Those with a mind to “live for today“ are apt to be indifferent to h
20、ealth risks that have a very long incubation period. Although this is short-sighted, it does make sense to discount long-term risks more than short-term ones. 18._ One commonly used measure to deal with such problems is a concept called years of potential life lost. The idea is that for a 25-year-ol
21、d, doing something that will kill him in 5 years is much more “costly“ than doing something that will kill him in 40 years. Both may involve the same element of risk the same probability of eventually dying from that activity but a risk that may cause immediate damage is much more costly than one fo
22、r which the piper neednt be paid for a long time. In the first case, he will have his normal life span cut short by about 45 years; in the latter case, the deficit is about 5 years. Thinking about matters in this light inevitably causes a reassessment of many of the threats to health. For instance,
23、heart disease is the single largest killer of Americans, way in front of cancer or strokes. 19._ Hence, more YPLLs are lost to cancer than to heart disease despite the greater incidence of fatal heart cases. Specifically, cancers claim about 25 percent more YPLLs than heart disease. The concept of Y
24、PLLs has an important, if controversial, influence on issues in health care economics. It is frequently argued that money devoted to medical research on curing diseases should be divided up on the basis of the number of lives lost to each disease. Thus, some critics of the massive levels of funding
25、devoted to AIDS research claim that compared to killers such as heart disease and cancer AIDS receives a disproportionately high support. 20._ Put differently, finding a cure for AIDS would be likely to add about 25 to 30 years to the life of each potential victim. Finding a cure for heart disease,
26、although it might save far more lives, would probably add only another 5 to t0 years to the life of its average victim. The assessment of the seriousness of a risk changes, depending upon whether we ask how many lives it claims or how many YPLLs it involves. Some of the differences are quite strikin
27、g. For instance, accidental deaths appear relatively insignificant compared to cancer and heart disease when we just count the deaths caused. But once we look at the number of lost years, accidents loom into first place among the killers of Americans. These data show that we need to ask not only how
28、 large a risk is but also when it becomes payable. A However, heart disease tends to strike the elderly in much greater proportions than younger people. Cancer, by contrast, kills fewer people but tends to strike somewhat earlier than heart disease. B After all, when virtually any of us is confronte
29、d with the choice of doing something likely to kill us today versus doing something likely to kill us in two decades, the choice is going to be the lesser of the two evils. C Many diseases that once struck terror into hearts have either been completely eliminated or brought under control. Although A
30、IDS is a notable exception, few new mass killers have come along to replace the ones that have been eliminated. D Other things being equal, the sooner a risk causes damage or death, the more that risk is to be avoided. E That criticism fails to consider the fact that AIDS, by virtue of striking peop
31、le 20, 000 deaths per year, bad as that is, might suggest. F One major problem with any comparison of health risks especially life-threatening ones is that they differ enormously in their immediacy. 国家公共英语五级（阅读理解）练习试卷 8答案与解析 Part A Directions: Read the following texts and answer the questions which
32、accompany them by choosing A, B, C or D. Mark your answers on ANSWER SHEET 1. 【知识模块】 阅读理解 1 【正确答案】 B 【试题解析】 本文是关于生物技术的，词汇有一定的难度。面对技术文章中出现的生词， 考生要 不同对待。对于那些名词类的生词不必追究它们的意思，可以用简单的符号将这些 较难的名词简单化：对于那些动词、形容词就要通过对上下文的仔细推敲来判断其意义。 在阅读第一遍时不要因为生词而停顿，要耐心地阅读完以获得主题思想。生词多的文章不 一定问题也难回答，因此阅读第一遍的时候要以获取主题思想为目的，不要因为生词
33、多而 影响阅读速度，本文主题是关于烟草在公众中的形象可能会因为基因技术而改变。接着文 章说明了新技术的具体内容。该题是主旨判断题，根据全文的意思应是 B。 【知识模块】 阅读理解 2 【正确答案】 C 【试题解析】 与该词意思最接近的是 C。 【知识模块】 阅读理解 3 【正确答案】 D 【试题解析】 是非判断题。认真研读题项句子，与原文进行对比，排除与原文意思相近的 选项，剩下的就是该题的答案。 A与第二段中的 somatotropinan extremely costly drugused to treat dwarfism意思一致。 B与第二段最后一句话中的 far less numer
34、ous cell component 致。 C与第二段倒数第二句中的 which is responsible for converting light into food一致。排除 了以上的可能性， D就是答案，可以从第二段第二句找出依据。 【知识模块】 阅读理解 4 【正确答案】 B 【试题解析】 A中表达的意思与最后一句中的 chloroplasts(叶绿体 )are abundant相反。 B 中的意思与最后一句意思一致，是该题的答案。 C表达的意思是nucleus(细胞核 )和 chloroplast是植物细胞中所包含的全部 organelles(细胞器官 )，而原文的 意思是叶绿体
35、和细 胞核是植物细胞中众多细胞器官中的两个，这两句话意义不完全相等。 D表达的意思与该 段的第三句意思不符合。 【知识模块】 阅读理解 5 【正确答案】 A 【试题解析】 推理题。理解文章主题是关键。由于基因技术的发展，原来有害的、致癌的 物质可能会对人类有帮助。这是从全文中可以推断出的。 【知识模块】 阅读理解 Part B Directions: In the following article some paragraphs have been removed. For Questions 66-70, choose the most suitable paragraph from th
36、e list A-F to fit into each of the numbered gaps. There is one paragraph which does not fit in any of the gaps. Mark your answers on ANSWER SHEET 1. 【知识模块】 阅读理解 6 【正确答案】 C 【试题解析】 文章第一 段提到美国人对健康非常担心，这种担心使得美国人比较在意他们 的健康，该段结尾处提到 “Americans are far healthier now than they have ever been” ，在 选项 C中提到 “man
37、y diseases have either been completely eliminated or brought under control ”这是美国人更健康的原因，从此可以判断C为正确项。 【知识模块】 阅读理解 7 【正确答案】 F 【试题解析】 在该 空白处前一段提到人类永远关注的是对人的健康和生命构成的各种威胁。 在选项 F中提到了 “health risks”和 “life-threatening ones”上下文连贯，因此 F为正确项。 【知识模块】 阅读理解 8 【正确答案】 B 【试题解析】 在该空白段之前讲到在就健康风险作选择时，应牢记冒险和遭受其带来的后 果之间的
38、可能时间距，在 B选项中，提到当我们面临这种选择时，我们的选择往往是两害 之较轻者。从而可以推出 B为正确项。 【知识模块】 阅读理解 9 【正确答案】 A 【试题解析】 在该空白处之前谈到不同疾病对生命带来的威胁，其中提到长期危害和短期 危害，这一点也使得许多人对不同疾病对健康的威胁作出重新评价。在末句提到心脏病是 导致死亡的最严重的疾病，远远高于癌症或中风。在选项 A中提到心脏病在老年人中病发 率高于年轻人，而相比心脏病癌症在年轻人中发病率高。从此可以推断 A为正确项。 【知识模块】 阅读理解 10 【正确答案】 E 【试题解析】 在该题前一段结尾处提到一些批评家指出用于研究 AIDS的经费过高，与其病 发率不成比例，在选项 E中提到该批评没有考 虑到这样一个事实：由于 AIDS主要侵袭二 三十岁的年轻人，与每年 20， 000这个简单的死亡人数所表示的含义相比， AIDS导致的 YPLL 要远远大得多。从此判断 E为正确项。 【知识模块】 阅读理解
