大学英语四级50及答案解析.doc
《大学英语四级50及答案解析.doc》由会员分享,可在线阅读,更多相关《大学英语四级50及答案解析.doc(28页珍藏版)》请在麦多课文档分享上搜索。
1、大学英语四级 50 及答案解析(总分:746.58,做题时间:130 分钟)一、Writing (30 minutes)(总题数:1,分数:30.00)1.For this part, you are allowed 30 minutes to write a short essay in honor of teachers on the occasion of “Teachers Day”. You should write at least 120 words following the outline given below: 1.向老师致以节日祝贺 2.从一件难忘的事回忆老师的教诲和无
2、私的奉献 3.我如何回报老师的关爱 (分数:30.00)_二、Reading Comprehensio(总题数:1,分数:71.00)SURVIVING IN SPACE Motion sickness troubles more than two-thirds of all astronauts upon reaching orbit, even veteran test pilots who have never been airsick. Though everyone recovers after a few days in space, body systems continue t
3、o change. Deprived(丧失) of gravity information, a confused brain creates visual illusions. Body fluids surge to chest and head. The heart enlarges slightly, as do other organs. Sensing too much fluid, the body begins to discharge it, including calcium, electrolytes (解液) and blood plasma (血浆). The pro
4、duction of red blood ceils decreases, rendering astronauts slightly anaemic (贫血的). With the loss of fluid, legs shrink. Spinal (脊骨的) discs expand, and so does the astronaut-who may gain five centimeters and suffer backache. Though the .process may sound terrible, astronauts adjust to k, come to enjo
5、y it and seem no worse for wear-at least for short missions such as space shuttle flights that last a week or two. During longer flights, however, physiology enters an unknown realm. As director of Russias Institute for Biomedical Problems from 1968 to 1988, Oleg Gazenko watched cosmonauts return fr
6、om long flights unable to stand without fainting, needing to be carried from the spacecraft. “We are creatures of the Earth,” Gazenko told me. “These changes are the price of a ticket to space“. Americans returning from months-long flights on Mir, the Russian space station, also paid the price, suff
7、ering losses in weight, muscle mass and bone density. NASA geared up to see how-even if-humans would survive the most demanding of space ventures, a mission to Mars, which could last up to three years. “We dont even know if a broken bone will heal in space,“ said Daniel Goldin, NASAs administrator.
8、To get answers in 1997 Goldin established the National Space Biomedical Research Institute (NSBRI), a panel of experts from a dozen leading universities and research institute. NSBRI will study biomedical problems and by 2010 will present NASA with a “go“ or “no go“ recommendation on a Mars mission.
9、 Jeffrey Sutton, leader of the medical systems team at the NSBRI, has treated the head trauma, wounds, kidney stones and heart rhythm irregularities that one could encounter on the way to Mars. On the spacecraft he envisions, Mars-hound in the year, say, 2018, there may lurk harmful bacteria or carb
10、on monoxide. No problem. The deadly substances will be detected by smart sensors-microprocessors no bigger than a thumbnail-that wander at will through the spacecraft, communicating their finds to a computer that warns the crew. To cope with infection, Sutton plans a factory to make drugs, even new
11、ones, to cope with possible organisms on Mars. Miniature optical and ultrasound devices will image body and brain, while a small X-ray machine keeps track of any bone loss. Smart sensors embedded in clothing will monitor an astronauts vital functions. The crew will be able to craft body parts, Sutto
12、n says, precisely tooled to an astronauts personal anatomy and genome stored in computer memory. Researchers are building artificial liver, bone and cartilage (软骨) tissue right now. Lying in wait beyond the Earths atmosphere, solar radiation poses additional problems. The sun flings billions of tons
13、 of electrically charged gas into space, relegating Earths volcanic eruptions to mere hiccups. Nevertheless, NASA officials are confident the accurate monitoring will warn astronauts of such events, allowing the crew to take refuge in an area where polyethylene (乙烯) shielding will absorb the radiati
14、on. A second kind of radiation, cosmic rays from the Milky Way or other galaxies, is a more serious threat-possessing too much energy, too much speed for shielding to be effective. “Theres no way you can avoid them,“ says Francis Cxueinotta, manager of NASAs Johnson Space Centre. “They pass through
15、tissue, striking ceils and leaving them unstable, mutilated or dead. Understanding their biological effects is a priority.“ Another major concern is the psychological health of astronauts. And theres a new stressor on a three-year Mars Mission-people, other members of the crew. NASA found that the s
16、tresses of isolation and confinement can be brought on rapidly simply by giving people few tasks. Mir astronaut Andrew Thomas described how six astronauts were confined in a 12-foot square room for a week. “If you give them little to do, stress can be achieved in a couple of days, says Thomas. Will
17、NSBRI meet Daniel Goldins 2010 deadline for a decision on Mars? “Yes, we will perhaps even before. Were very confident,“ says Laurence Young, the director of NABRI. Mean while some of NSBRIs research may bear fruit on Earth. The institute has made one discovery that promises to save many people at r
18、isk of sudden cardiac death, usually brought on by a heart rhythm disorder called ventricular fibrillation. This kills 225,000 people in the US each year. Richard Cohen, head of the NSBR1 cardiovascular (心血管的) team, explained that zero gravity may-emphasizing “may“-incite this condition in astronaut
19、s. So the team invented a noninvasive diagnostic device that measures extremely tiny changes in heart rhythm. The team found that the device can be used as part of a standard stress test to identify patients at risk. Then pacemaker-like devices can be implanted to regulate the rhythm disorder. “This
20、 technology has the potential to save hundreds of thousands of lives,“ says Cohen. “NASA can be proud.“ Such discoveries are no accident, says Michael E. DeBakey, a cardiovascular surgeon who has saved many hearts himself. “The key word is research. When I was a medical student and a patient came to
21、 the hospital with a heart attack, things were mostly a matter of chance. Today theres a better than 95 per cent chance of surviving. Now that all comes from research. The unfortunate thing is that there are people, even some scientists, who look at the money that goes to NASA and we could use the m
22、oney to support our work. Thats very short sighted. The more research thats done in any area of science, the better off everyone is going to be.“ (分数:71.00)(1).Everyone who travels in space suffers from feelings of motion sickness initially. (分数:7.10)A.YB.NC.NG(2).Astronauts are likely to increase i
23、n height while in space. (分数:7.10)A.YB.NC.NG(3).Its important for astronauts to exercise in order to keep their muscles fit. (分数:7.10)A.YB.NC.NG(4).Scientists have found a way of protecting astronauts from solar radiation. (分数:7.10)A.YB.NC.NG(5).If astronauts are given tasks to do, they quickly begi
24、n to suffer from stress. (分数:7.10)A.YB.NC.NG(6).Scientists aim to develop technology that can recognize psychological states. (分数:7.10)A.YB.NC.NG(7).The passage mainly describes the psychological health risks during the voyage to Mars. (分数:7.10)A.YB.NC.NG(8).In the US each year, sudden cardiac death
- 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:
- 大学 英语四 50 答案 解析 DOC
