首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
考研
The following paragraphs are given in a wrong order. You are required to reorganize these paragraphs into a coherent text by cho
The following paragraphs are given in a wrong order. You are required to reorganize these paragraphs into a coherent text by cho
admin
2009-04-26
62
问题
The following paragraphs are given in a wrong order. You are required to reorganize these paragraphs into a coherent text by choosing from the list A—G. The first and the last paragraphs have been placed for yous.
A. The strain of HIV that was discovered in Sydney intrigues scientists because it contains striking abnormalities in a gene that is believed to stimulate viral duplication. In fact, the virus is missing so much of this particular gene—known as nef, for negative factor—that it is hard to imagine how the gene could perform any useful function. And sure enough, while the Sydney virus retains the ability to infect T cells—white blood cells that are critical to the immune system’s ability to ward off infection—it makes so few copies of itself that the most powerful molecular tools can barely detect its presence.
B. If this speculation proves right, it will mark a milestone in the battle to contain the late-20th century’s most terrible epidemic. For in addition to explaining why this small group of people infected with HIV has not become sick, the discovery of a viral strain that works like a vaccine would have far-reaching implications. "What these results suggest", says Dr. Barney Graham of Tennessee’s Vanderbilt University, "is that HIV is vulnerable and that it is possible to stimulate effective immunity against it".
C. But as six years stretched to 10, then to 14, the anxiety of health officials gave way to astonishment. Although two of the recipients have died from other causes, not one of the man’s contaminated blood has come down with AIDS. More telling still, the donor is also healthy. In fact his immune system remains as robust as if he had never tangled with HIV at all. What could explain such unexpected good fortune?
D. At the very least, the nef gene offers an attractive target for drug developers. If its activity can be blocked, suggests Deacon, researchers might be able to bring the progression of disease under control, even in people who have developed full-blown AIDS. The need for better AIDS-fighting drugs was underscored last week by the actions of a U.S. Food and Drug Administration advisory panel, which, recommended speedy approval of two new AIDS drugs. Although FDA commissioner David Kessler was quick to praise the new drugs, neither medication can prevent or cure AIDS once it has taken hold. What scientists really want is a vaccine that can prevent infection altogether. And that’s what makes the Sydney virus so promising—and so controversial.
E. A team of Australian scientists has finally solved the mystery. The virus that the donor contracted and then passed on, the team reported last week in the journal Science, contains flaws in its genetic script that appear to have rendered it harmless. "Not only have the recipients and the donor not progressed to disease for 15 years", marvels molecular biologist Nicholas Deacon of Australia’s Macfarlane Burnet Centre for Medical Research, "but the prediction is that they never will". Deacon speculates that this "impotent" HIV may even be a natural inoculant that protects its carriers against more virulent strains of the virus.
F. But few scientists are enthusiastic about testing the proposition by injecting HIV—however weakened—into millions of people who have never been infected. After all, they note, HIV is a retrovirus, a class of infectious agents known for their alarming ability to integrate their own genes into the DNA of the cells they infect. Thus once it takes effect, a retrovirus infection is permanent.
G. About 15 years ago, a well-meaning man donated blood to the Red Cross in Sydney, Australia, not knowing he has been exposed to HIV-1, the virus that causes AIDS. Much later, public health officials learned that some of the people who got transfusions containing his blood had become infected with the same virus; presumably they were almost sure to die.
Order: G is the first paragraph and F is the last.
选项
答案
A
解析
转载请注明原文地址:https://kaotiyun.com/show/Yei4777K
0
考研英语一
相关试题推荐
Themainideaofthefirstparagraphisthat______.Itcanbeinferredfromthepassagethat______.
Thesentence"Aftereachrainshower,anotherInternetmillionairesprangup"(Paragraph1)means______.Whatcanbeinferred
ThewriterwarnsAmericansthat______.Thewritergivestheexampleofbreadtoshowthat______.
Bysayingthatacountry’sagriculturalsurplusesoften"complicate"itseconomy,theauthormeans______.Whydogovernmentss
YouhavejustcomebackfromtheU.S.asamemberofaSino-Americanculturalexchangeprogram.WritealettertoyourAmerican
Leadingdoctorstodayweighinonthedebateoverthegovernment’sroleinpromotingpublichealthbydemandingthatministersi
Whenitcomestotheeconomy,pessimismisinandgoodoldAmericanoptimismisout.Fromtheheadlinesinthenewspaperstothe
HenricIbsen,authoroftheplay"ADoll’sHouse",inwhichapretty,helplesshousewifeabandonsherhusbandandchildrentose
Everyone,itseems,hasahealthproblem.AfterpouringbillionsintotheNationalHealthService,Britishpeoplemoanaboutdir
随机试题
“控制标准Z值由某一目标函数的最大值或最小值构成”这一特点所对应的控制类型是()
Thereseemedtobeno______totheirfinancialproblems.
患者突发胸痛,吸气时加重,屏气可减轻,提示病变累及到()
关于泻下剂使用注意,说法错误的是
下列关于会计凭证的保管的说法中,不正确的是()。
注意事项1.申论考试是对应考者阅读理解能力、综合分析能力、提出和解决问题能力、文字表达能力和贯彻执行能力的测试。2.作答参考时限:阅读材料30分钟。作答90分钟。3.仔细阅读给定资料,按照后面提出的“作答要求”依次作答。4.考生可以
一位员工每天骑自行车上班,从他家到公司共有5个十字路口,假设他在每个十字路口遇到红灯是相互独立的,且首、末两个十字路口遇红灯的概率均为,其余3个十字路口遇红灯的概率均为。则该员工在第三个十字路口第一次遇到红灯的概率是
设总体x~N(μ,σ2),其中σ2未知,s2=,样本容量n,则参数μ的置信度为1-α的置信区间为().
时间线只能应用于什么的对象______。A.分割B.分离C.分开D.分层
HowhasMr.HumphriesbeenlearningSpanish?
最新回复
(
0
)