1、考研英语（阅读）模拟试卷 424 及答案与解析Part ADirections: Read the following four texts. Answer the questions below each text by choosing A, B, C or D. (40 points)0 The cause of Alzheimers disease is unknown, but various studies suggest that its risk factors extend beyond genetics. Some studies have associated the d
2、isease with a lack of physical activity. Others have linked Alzheimers disease to a lack of stimulating brainworkfitting a use-it-or-lose-it situation of cognitive decline.A new study supports the view that both kinds of inactivity pose risks. People who have the memory loss, confusion, and disorien
3、tation of Alzheimers disease in old age were generally less active physically and intellectually between the ages of 20 and 60 than were people who dont have the disease, according to study coauthor Robert P. Friedland, a neurologist at Case Western Reserve University School of Medicine in Cleveland
4、, and his colleagues.After establishing an average overall activity level for all the studys participants, the researchers discovered that the Alzheimers patients were nearly four times as likely as the people without Alzheimers to fall below that average. In particular, the non-Alzheimers volunteer
5、s had devoted more time on average between ages 40 and 60 to intellectual activities and less to passive ones than had those who developed the disease. The only single activity in which Alzheimers patients on average significantly outperformed their counterparts was watching television, Friedland sa
6、ys.While certain genetic factors seem to influence the brain deterioration associated with Alzheimers, these dont account for all cases of the disease. Indeed, studies of genetically similar people living in separate countries show divergent rates of Alzheimers disease.The new study accounted for di
7、fferences in education and income but not occupation. It doesnt point to a cause of Alzheimers or even predict who might develop the disease, but it does reinforce the value of remaining physically and mentally active, Friedland says. From an evolutionary standpoint, people are still physically desi
8、gned to be active hunters and gatherers. “Being a couch potato,“ he says, “is not our natural state.“Intellectual stimulation may work the same way, he says. Studies indicate that a higher educational level makes a person less likely to develop Alzheimers disease. Some researchers suggest that chall
9、enging the brain builds reserves of functional brain tissue that protect people against the disease.“This is a very intriguing study“ built on “extremely rigorous“ data collection, says Mary S. Mittelman, a scientist at New York University School of Medicine. However, she wonders why some people are
10、 active during their middle years while others arent. Could it be that a sedentary lifestyle really contributes to the development of Alzheimers, or does the illness begin early in life and subtly steer a person toward such a lifestyle? “ It could be a combination of both,“ Friedland says.1 From the
11、 first two paragraphs, we learn that_.（A）Alzheimers disease has nothing to do with genetic transmission（B） intellectual work may reduce the risk of getting Alzheimers disease（C） an inactive child is more likely to get Alzheimers disease than an active one（D）a lack of physical exercise has been prove
12、d to be a cause of Alzheimers disease2 Alzheimers patients watching television is mentioned to suggest that_.（A）watching television may do great harm to ones health（B） there is a controversy over whether Alzheimers patients should watch TV（C） one intellectual activity Alzheimers patients did more is
13、 watching television（D）passive activities such as watching television may lead to Alzheimers disease3 According to the study, Alzheimers disease may have something to do with peoples_.（A）profession（B） living environment（C） salary（D）nationality4 The word “sedentary“(Line 3, Para. 7) means_.（A）involvi
14、ng much sitting（B） showing physical fatigue（C） involving much standing（D）showing mental tiredness5 To which of the following statements would Friedland most likely agree?（A）Educational difference is a cause of Alzheimers disease.（B） People should participate actively in hunting and gathering.（C） Peo
15、ples lifestyle may lead to Alzheimers disease and vice versa.（D）Intellectual work may ward off Alzheimers disease better than physical work.5 The immune system is equal in complexity to the combined intricacies of the brain and nervous system. The success of the immune system in defending the body r
16、elies on a dynamic regulatory communications network consisting of millions and millions of cells. Organized into sets and subsets, these cells pass information back and forth like clouds of bees swarming around a hive. The result is a sensitive system of checks and balances that produces an immune
17、response that is prompt, appropriate, effective and self-limiting.At the heart of the immune system is the ability to distinguish between self and non-self. When immune defenders encounter cells or organisms carrying foreign or non-self molecules, the immune troops move quickly to eliminate the inva
18、ders. Virtually every body cell carries distinctive molecules that identify it as self. The bodys immune defenses do not normally attack tissues that carry a self marker. Rather, immune cells and other body cells coexist peaceably in a state known as self-tolerance. When a normally functioning immun
19、e system attacks a non-self molecule, the system has the ability to remember the specifics of the foreign body. Upon subsequent encounters with the same species of molecules, the immune system reacts accordingly. With the possible exception of antibodies passed during lactation, this so-called immun
20、e system memory is not inherited. Despite the occurrence of a virus in your family, your immune system must learn from experience with the many millions of distinctive non-self molecules in the sea of microbes in which we live. Learning necessitates producing the appropriate molecules and cells to m
21、atch up with and counteract each non-self invader.Any substance capable of stimulating an immune response is called an antigen. Tissues or cells from another individual (except an identical twin, whose cells carry identical self-markers) act as antigens; because the immune system recognizes transpla
22、nted tissues as foreign, it rejects them. The body will even reject nourishing proteins unless they are first broken down by the digestive system into their primary, non-antigenic building blocks. An antigen announces its foreignness by means of intricate and characteristic shapes called epitopes, w
23、hich stick out from its surface. Most antigens, even the simplest microbes, carry several different kinds of epitopes on their surface, some may even carry several hundred. Some epitopes will be more effective than others at stimulating an immune response. Only in abnormal situations does the immune
24、 system wrongly identify self as non-self and execute a misdirected immune attack. The result can be so-called autoimmune disease. The painful side effects of these diseases are caused by a persons immune system actually attacking itself.6 We know from the text that the immune system_.（A）is no less
25、complicated than the nervous system（B） far exceeds the human brain in intricacy（C） is enclosed by numerous sensitive cells（D）results in an effective communications network7 The principal task of the immune system is to_.（A）recognize and eliminate all foreign molecules that enter the body（B） remove a
26、ll the substances that invade the body organisms（C） defend the body from the attacks of different viruses and bacteria（D）identify and specify all non-self molecules it encounters8 The remembering power of a persons immune system is_.（A）mostly descended from his/her ancestors（B） partially passed down
27、 from his/her mother（C） mainly acquired through fighting against foreign cells（D）basically generated by its communications network9 A tissue transplanted from father to daughter would be less acceptable than that transplanted between twins because_.（A）the ages of the twins tissues are exactly alike（
28、B） the twins tissues have the same self-markers（C） the father and daughter are different in sex（D）the twins immune systems possess identical memory10 The main idea of the text may be generalized as_.（A）the success of the immune system in distinguishing foreign substances（B） the normal and abnormal a
29、ctivities of the immune system in the body（C） the unfavorable effects of the immune system on organ transplantation（D）the essential duties of the immune system in guarding the body10 Community cancer clusters are viewed quite differently by citizen activists than by epidemiologists. Environmentalist
30、s and concerned local residents, for instance, might immediately suspect environmental radiation as the culprit when a high incidence of cancer cases occurs near a nuclear facility. Epidemiologists, in contrast, would be more likely to say that the incidences were “inconclusive“ or the result of pur
31、e chance. And when a breast cancer survivor, Lorraine Pace, mapped 20 breast cancer cases occurring in her West Islip, Long Island, community, her rudimentary research efforts were guided more by hopethat a specific environmental agent could be correlated with the cancersthan by scientific method.Wh
32、en epidemiologists study clusters of cancer cases and other noncontagious conditions such as birth defects or miscarriage, they take several variables into account, such as background rate (the number of people affected in the general population), cluster size, and specificity (any notable character
33、istics of the individual affected in each case). If a cluster is both large and specific, it is easier for epidemiologists to assign blame. Not only must each variable be considered on its own, but it must also be combined with others. Lung cancer is very common in the general population. Yet when a
34、 huge number of cases turned up among World War II shipbuilders who had all worked with asbestos, the size of the cluster and the fact that the men had had similar occupational asbestos exposures enabled epidemiologists to assign blame to the fibrous mineral.Although several known carcinogens have b
35、een discovered through these kinds of occupational or medical clusters, only one community cancer cluster has ever been traced to an environmental cause. Health officials often discount a communitys suspicion of a common environmental cause because citizens tend to include cases that were diagnosed
36、before the afflicted individuals moved into the neighborhood. Add to this is the problem of cancers latency. Unlike an infectious disease such as cholera, which is caused by a recent exposure to food or water contaminated with the cholera bacterium, cancer may have its roots in an exposure that occu
37、rred 10 to 20 years earlier.Do all these caveats mean that the hard work of Lorraine Pace and other community activists is for nothing? Not necessarily. Together with many other reports of breast cancer clusters on Long Island, the West Islip situation highlighted by Pace has helped epidemiologists
38、lay the groundwork for a well-designed scientific study.11 The “hope“ mentioned in Paragraph 1 refers specifically to Paces desire to_.（A）help reduce the incidence of breast cancer in future generations（B） improve her chances of surviving breast cancer（C） determine the cause responsible for her own
39、breast cancer case（D）identify a particular cause for the breast cancer cases in West Islip12 The case of the World War II shipbuilders with lung cancer is an example of_.（A）an occupational cluster（B） a medical cluster（C） a radiation cluster（D）an environmental cluster13 The text suggests that the fac
40、t “only one community cancer cluster had ever been traced to an environmental cause“ (Para. 3) is most likely due to the_.（A）methodological difficulties in analyzing community cancer clusters（B） reluctance of epidemiologists to investigate environmental factors in cancer（C） lack of credibility of ci
41、tizen activists in claiming to have identified cancer agents（D）effectiveness of regulations restricting the use of carcinogens in residential areas14 Activists may mistakenly consider a particular incidence of cancer as part of a community cluster despite the fact that_.（A）the affected individual ne
42、ver worked with any carcinogenic material（B） the cancer was actually caused by an exposure long time ago（C） the size of the cluster is too small to be meaningful（D）the cancer actually arose in a different geographic location 15 The word “caveats“ (Line 1, Para. 4) refers to_.（A）refusals by epidemiol
43、ogists to examine the work of Pace and other activists（B） potential flaws in amateur studies of cancer cluster（C） warnings by activists concerning environmental dangers in their communities（D）tendencies of activists to assume environmental causes for cancer15 Doctors are having a hard go of things.
44、Squeezed by falling refund, soaring malpractice insurance and punishing patient loads, they shouldnt have much to fear from the likes of Wal-Mart. But the fact is, the greeter in the red vest is increasingly going toe-to-toe with the doctor in the white coatand winningthanks to the growing phenomeno
45、n of retail health clinics.Retail clinicsfree-standing, walk-in medical providers located in drug stores, shopping malls and stores like Wal-Mart, Target and Walgreensare rapidly becoming to the health-care industry what Fotomat was to the camera world. There are roughly 1,000 clinics now operating
46、in the US, offering acute care for such routine problems as throat infections and earaches as well as providing diabetes and cholesterol (a white substance found in animal tissues and various foods) screenings, routine checkups and vaccinations (the introduction of preventive medicine into the body
47、to produce immunity to a specific disease). The fees are lowand conspicuously posted; nearly all of the clinics treat both the insured and uninsured, and there is little or no waiting time. With 50 million Americans lacking health insurance and family budgets collapsing under the weight of medical c
48、osts, whats not to like about the clinics?Plenty, say physicians associations, whose members warn that clinicswhich are typically staffed by nurse practitioners and are positioned in stores that also sell prescriptionswill be inclined to misdiagnose and overprescribe. Worse, they are not built to pr
49、ovide long-term care for chronic conditions such as hypertension (elevation of the blood pressure), and they threaten the ideal of a lasting doctor-patient relationship, denying consumers a so-called “medical home“.Those, at least, are the arguments, though it was impossible to know how well-founded they wereuntil now. In twin studies published this week in the Annals of Internal Medicine, the Rand Corp. reports on an extens
