[外语类试卷]大学英语六级模拟试卷33及答案与解析.doc
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1、大学英语六级模拟试卷 33及答案与解析 一、 Part I Writing (30 minutes) 1 For this part, you are allowed 30 minutes to write a composition on the topic Learn to Give up Wisely. You should write at least 150 words according to the outline given below in Chinese: 1我们应该 学会明智地放弃 2该放弃而不放弃的危害 3在什么情况下我们应该明智地放弃 Learn to Give up
2、 Wisely 二、 Part II Reading Comprehension (Skimming and Scanning) (15 minutes) Directions: In this part, you will have 15 minutes to go over the passage quickly and answer the questions attached to the passage. For questions 1-4, mark: Y (for YES) if the statement agrees with the information given in
3、 the passage; N (for NO) if the statement contradicts the information given in the passage; NG (for NOT GIVEN) if the information is not given in the passage. 2 New Hopes for Preventing AIDS The success of anti-retroviral(抑止肿瘤病毒 ) drugs in treating HIV is getting researchers at the 16th Internationa
4、l AIDS conference excited at the prospect that the potent(效力大的 ) medicines might be exploited to perform double duty. Why not use the power of these ARVs to prevent an HIV transmission or infection from taking hold in the first place? Bill and Melinda Gates asked that provocative question on the ope
5、ning day of the conference, and are commit- ting their considerable financial resources toward finding an answer. In their remarks, they highlighted the need to develop microbicides(杀菌剂 ) and oral prevention drugs while we wait for a vaccine. And they will get their first hint at how smart their dec
6、ision was this Thursday, when scientists from West Africa report the initial results from the first trial studying an oral prevention drug. So how realistic are the Gates in expecting even more from the ARVs? “I do think the range of prevention options we have within the next decade will greatly exp
7、and,“ says Dr. Helene Gayle, President of Care USA and co-chair of the conference. “The biologic plausibility(似乎有理 ) for both microbicides and oral prevention drugs is so great.“ Dr. Mark Dybul, U.S. Global AIDS Coordinator, said that if a microbicide or prevention drug becomes available to protect
8、people from infections, they would be funded under the Presidents Emergency Plan for AIDS Relief if countries chose to use them. “We would support all of that; it would be perfectly within our mandate to do all that,“ he told TIME. Preventing HIV is the only way to keep the number of new infections
9、that occur each year 4 million from growing. And yet prevention strategies, always the ugly stepsister to treatment programs, have not really taken hold in the developing nations where the rate of infection is highest. An effective vaccine, of course, is the ultimate prevention weapon, but as the Ga
10、tes pointed out, an HIV shot is still a long way off. In the meantime, microbicides could be one way to co-opt ARVs into the prevention war; these are chemical compounds, usually in the form of a gel or cream, that women can use vaginally prior to intercourse to stop the transmission of HIV its the
11、same idea behind spermicides(杀精子剂 ), which are chemical barriers to sperm entering the vagina and causing pregnancy. Its an elegantly simple approach, made even simpler by the fact that researchers didnt really have to start from scratch to come up with new anti-HIV compounds; they already have them
12、 in the ARVs, which now interrupt the virus from infecting cells at various points in its life cycle. The key difference is that in a microbicide, the drugs are being used in healthy people rather than in those infected with HIV. When ARVs are used for treatment, both doctors and patients are willin
13、g to tolerate a higher level of side effects after all, if the choice is between dying from HIV-AIDS and side effects, most patients opt for the latter. If the drugs are to be used to prevent infection, however, everything changes; understandably, healthy people arent as likely to accept the same le
14、vel of side effects and toxicities as those already infected. Thats why clinical trials are so significant. So far, there are 30 40 different microbicide candidates being tested in animals, and five trials in Ghana, Nigeria and other developing nations at the most advanced stages of testing in women
15、. Dr. Gita Ramjee, of the HIV Prevention Research Unit in Durban, South Africa, has worked with all five, and is hopeful that they will prove effective and make an impact on the disease. Because these latest microbicides are reformulated ARVs, however, the problem of the virus becoming resistant to
16、them is a potential drawback. Dr. Peter Piot, of UNAIDS, suggests basing microbicides only on the drugs do not make it through the pharmaceutical pipeline many are rejected because they dont maintain high enough levels in the blood to treat an HIV infection; but could be sufficiently powerful to pre
17、vent transmission. But Zeda Rosenberg, CEO of International Partnership for Microbicides, which has sponsored a number of the trials, believes that since microbicides arent designed to enter the blood, stream and suppress HIV there, resistance wont be as huge a hurdle as it is for ARVs used in treat
18、ment. “The studies so far, with most of the ARV products, suggest very low levels of systemic absorption,“ she says. “It may be that there is insufficient absorption to select for resistance. But we wont know that answer until we do the efficacy trials.“ The first of these results, from Nigeria, wil
19、l be released in September 2007. Even if they prove to be effective, Ramjee and others stress that microbicides whether they come in the form of a gel or cream applied before intercourse, or as part of a delayed release ring inserted into the cervix that can provide the drug for anywhere from 30 to
20、90 days are not a physical barrier to HIV. At best, microbicides may be 80% effective in preventing the transmission of the virus during intercourse. To improve the chances that the virus doesnt slip by, however, there is always the possibility of combining the ARVs, in the same way that doctors cur
21、rently do to treat infected patients. On the ground, however, Ramjee noted that its sometimes hard to keep patients enrolled. Not only do women often face opposition from their male partners to using the microbicide, there is the reality that many of the women enrolled end up getting pregnant, and a
22、s a result, have to drop out.(The trial sponsors, including USAID, NIIH and the Gates Foundation, do continue to provide family planning and other pre and post natal services to these women, if they choose to use them.) Even more tantalizing(让人着急的 ) than the microbicides is the idea of taking a pill
23、 before intercourse or other high-risk behavior, and thereby becoming protected from HIV. Drugs for pre-exposure prophylaxis (PrEPs=Prevention of or protective treatment for disease) were born from the success of programs that prevent mother-to-child transmission; since ARVs given to women pre: and
24、post delivery are effective in reducing the transmission of HIV to the child, and using ARVs before exposure to HIV have the same effect in protecting partners. Five trials, all involving two compounds, Tenofovir or Truvada, are now underway in Thailand, Botswana, Peru, West Africa and even the U.S.
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- 外语类 试卷 大学 英语六级 模拟 33 答案 解析 DOC
