[外语类试卷]大学英语六级模拟试卷691及答案与解析.doc
《[外语类试卷]大学英语六级模拟试卷691及答案与解析.doc》由会员分享,可在线阅读,更多相关《[外语类试卷]大学英语六级模拟试卷691及答案与解析.doc(24页珍藏版)》请在麦多课文档分享上搜索。
1、大学英语六级模拟试卷 691及答案与解析 一、 Part I Writing (30 minutes) 1 Directions: For this part, you are allowed thirty minutes to write a composition on the topic Rising Divorce Rates in China. You should write at least 150 words and you should base your composition on the outline given in Chinese below: 1. 描写图表反映
2、的问题 2. 你认为最近几年中国离婚高的原因是什么 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 in
3、formation given in 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. 1 New Hopes for Preventing AIDS The success of anti-retroviral (抑止肿瘤病毒 ) drugs in treating HIV is getting researchers at th
4、e 16th International AIDS conference excited at the prospect that the potent 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 questio
5、n on the opening day of the conference, and are committing their considerable financial resources toward finding an answer. In their remarks, they highlighted the need to develop microbicides and oral-prevention drugs while we wait for a vaccine. And they will get their first hint at how smart their
6、 decision 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
7、 expand,“ says Dr. Helene Gayle, President of Care USA and co-chair of the conference. “The biologic plausibility for both microbicides and oral-prevention drags is so great.“ Dr. Mark Dybul, U.S. Global AIDS Coordinator, said that if a microbicide or prevention drug becomes available to protect peo
8、ple 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 tha
9、t 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 G
10、ates 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 t
11、he 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
12、them 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 wi
13、lling 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 s
14、ame level of side effects and toxicities as those already infected. Thats why clinical trials are so significant. So far, there are 30 to 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
15、 in women. 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 resi
16、stant to them is a potential drawback. Dr. Peter Plot, 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 powerf
17、ul to prevent transmission. But Zeda Rosenberg, CEO of International Partnership for Microbicides, which has sponsored a number of the trims, believes that since microbicides arent designed to enter the bloodstream and suppress HIV there, resistance wont be as huge a hurdle as it is for ARVs used in
18、 treatment. “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 Nigeri
19、a, will 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 fro
20、m 30 to 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 d
21、octors currently 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 pregn
22、ant, and as 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
23、taking a pill 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
24、women pre-and-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
- 1.请仔细阅读文档,确保文档完整性,对于不预览、不比对内容而直接下载带来的问题本站不予受理。
- 2.下载的文档,不会出现我们的网址水印。
- 3、该文档所得收入(下载+内容+预览)归上传者、原创作者;如果您是本文档原作者,请点此认领!既往收益都归您。
下载文档到电脑,查找使用更方便
2000 积分 0人已下载
下载 | 加入VIP,交流精品资源 |
- 配套讲稿:
如PPT文件的首页显示word图标,表示该PPT已包含配套word讲稿。双击word图标可打开word文档。
- 特殊限制:
部分文档作品中含有的国旗、国徽等图片,仅作为作品整体效果示例展示,禁止商用。设计者仅对作品中独创性部分享有著作权。
- 关 键 词:
- 外语类 试卷 大学 英语六级 模拟 691 答案 解析 DOC
