1、公共英语四级-81 及答案解析(总分：100.00，做题时间：90 分钟)一、B Reading Compr(总题数：0，分数：0.00)二、BPart A/B(总题数：0，分数：0.00)三、BText 1/B(总题数：1，分数：20.00)It turns out that mens brains may literally be wired differently than those of women. Researchers say the differences could explain why the sexes seem more suited to certain type
2、s of tasks than their counterparts. For example, women seem to be hardwired for multitasking.Using imaging techniques, researchers at the University of Pennsylvania found men tended to display neural activity in one hemisphere of the brain for certain activities, while in women the activity bounces
3、across hemispheres. “These maps show us a stark difference and complementarity in the architecture of the human brain that helps provide a potential neural basis as to why men excel at certain tasks, and women at others.“ said Ragini Verma, a PhD in the department of Radiology at the University of P
4、ennsylvania.Past studies have shown sex differences in the brain, but the neural wiring connecting regions across the whole brain that have been tied to such cognitive skills has never been fully shown in a large population, the researchers said. Researchers found that in the cerebrum, the largest p
5、art of the brain, females displayed greater connectivity between the left and right hemispheres. Males, on the other hand, displayed greater connectivity within each hemisphere. By contrast, the opposite prevailed in the cerebellum, the part of the brain that plays a major role in motor control, whe
6、re males displayed greater inter-hemispheric connectivity and females displayed greater intra-hemispheric connectivity.These connections likely give men an efficient system for coordinated action, where the cerebellum and cortex participate in bridging between perceptual experiences in the back of t
7、he brain, and action, in the front of the brain, according to the authors. The female connections likely facilitate integration of the analytic and sequential processing modes of the left hemisphere with the spatial, intuitive information processing modes of the right side.The findings meshed with o
8、ther University of Pennsylvania studies in which females outperformed males on attention, word and face memory, and social cognition tests. Males performed better on spatial processing and sensorimotor speed. Those differences were most pronounced in the 12 to 14 age range. “Its quite striking how c
9、omplementary the brains of women and men really are,“ said Dr. Ruben Gur. He further pointed out detailed connectome maps of the brain will not only help us better understand the differences between how men and women think, but it will also give us more insight into the roots of neuropsychiatric dis
10、orders, which are often sex related.（分数：20.00）(1).Based on the first 2 paragraphs, which statement is true? A.Mens brains are the same as womens. B.The two hemispheres of brain work separately. C.Women are better at multitasking work than men. D.Men perform better than their female counterparts in a
11、ll fields.（分数：4.00）A.B.C.D.(2).Why are women good at certain tasks? A.They have great cognitive skills. B.Women are born with special abilities. C.Women have greater inter-hemispheric connectivity. D.Women can well coordinate the left and right hemispheres.（分数：4.00）A.B.C.D.(3).Which part of brain ca
12、n coordinate mens perceptual experience and action? A.Cerebrum. B.Left hemisphere. C.Right hemisphere. D.Cerebellum and cortex.（分数：4.00）A.B.C.D.(4).According to the study, which of the following is highly possible? A.Girls perform better than boys in a word dictation test. B.Generally speaking, boys
13、 are better at geometry than girls. C.Boys can remember and recognize people better than girls. D.Generally speaking, boys have longer concentration span than girls.（分数：4.00）A.B.C.D.(5).The text mainly centers on _. A.why men and women think differently B.why women are better at certain jobs than me
14、n C.the difference between mens and womens brains D.the reason why men and women have different performances from the perspective of brain structure（分数：4.00）A.B.C.D.四、BText 2/B(总题数：1，分数：20.00)The notion that some people can be overweight or obese and still remain healthy is a myth, according to a ne
15、w Canadian study.Even without high blood pressure, diabetes or other metabolic issues, overweight and obese people have higher rates of death, heart attack and stroke after 10 years compared with their thinner counterparts, the researchers found. “These data suggest that increased body weight is not
16、 a benign condition, even in the absence of metabolic abnormalities, and argue against the concept of healthy obesity or benign obesity.“ said researcher Dr. Ravi Retnakaran, an associate professor at the University of Toronto. He also added that metabolically healthy obese individuals are indeed at
17、 increased risk for death and cardiovascular events over the long term as compared with metabolically healthy normal-weight individuals.Its possible that obese people who appear metabolically healthy have low levels of some risk factors that worsen over time, the researchers suggest in the report, p
18、ublished online on Dec. 3 in the Annals of Internal Medicine. Dr. David Katz, director of the Yale University Prevention Research Center, welcomed the report. “Given the recent attention to the obesity paradox in the professional literature and pop culture alike, this is a very timely and important
19、paper,“ Katz said. Some obese people appear healthy because not all weight gain is harmful, “it depends partly on genes, partly on the source of calories, partly on activity levels, partly on hormone levels.“ he added.A number of things, however, work to increase the risk of heart attack, stroke and
20、 death over time. “Fat in the liver interferes with its function and insulin sensitivity.“ Katz said. This starts a domino effect, he explained this way: insensitivity to insulin causes the pancreas to compensate by raising insulin output. Higher insulin levels affect other hormones in a cascade tha
21、t causes inflammation. Fight-or-flight hormones are affected, raising blood pressure. Liver dysfunction also impairs blood cholesterol levels.In studies with follow-ups of over a decade, those who were overweight or obese but didnt have high blood pressure, heart disease or diabetes still had a 24 p
22、ercent increased risk for heart attack, stroke and death over 10 years or more, compared with normal-weight people, the researchers found.Greater risk for heart attack, stroke and death was seen among all those with metabolic disease regardless of weight, the researchers noted. As a result, doctors
23、should consider both body mass and metabolic tests when evaluating someones health risks, the researchers concluded.（分数：20.00）(1).Based on the first 2 paragraphs, which statement is NOT true? A.It is far from rare for a fat guy to remain healthy. B.The so-called healthy obesity or benign obesity has
24、 no negative effects in the long ran. C.Dr. Ravi Retnakaran doesnt agree with the concept of healthy obesity or benign obesity. D.High blood pressure, diabetes or other metabolic abnormalities may account for some healthy problems.（分数：4.00）A.B.C.D.(2).Peoples health is NOT affected by _ according to
25、 Katz. A.blood pressure B.hormone level C.how much one may eat D.how much sports one may take（分数：4.00）A.B.C.D.(3).What is “obesity paradox“? A.Fit and fat. B.Fat and harmful. C.Fat and thin. D.Overweight and obese.（分数：4.00）A.B.C.D.(4).Which factor starts the “domino effect“? A.Pancreas. B.Hormone. C
26、.Blood pressure. D.Fat in the liver.（分数：4.00）A.B.C.D.(5).Which of the following statements is true according to this passage? A.Weight gain is harmful to us. B.Overweight and healthy can not exist at the same time. C.Insulin sensitivity directly leads to high blood pressure. D.Overweight has no dire
27、ct connection with heart attack, stroke and death.（分数：4.00）A.B.C.D.五、BText 3/B(总题数：1，分数：20.00)The commuter train that crashed on Sunday in the Bronx shouldnt have derailed. The four people who died should still be alive. And they would be, if only New Yorks Metropolitan Transportation Authority had
28、deployed safety technology already used elsewhere and pushed by rail safety watchdogs for 40 years.A dazed engineer barreled into a 30 mph curve at 82 miles per hour. No alarm sounded to shake him out of his stupor. No automatic brakes kicked in. Disaster was guaranteed. However, five years ago, in
29、the wake of a fatal train accident in California, Congress mandated that all railroads install an automated braking system that could have prevented the crash. The deadline is 2015, but many railroadswary of the costhave failed to comply and are pushing for delay. Its fair to wonder what the MTA thi
30、nks of that strategy today.In 1969, after the NTSB investigated a deadly collision of two Penn Central trains in Connecticut, the board began calling for development of an automated backup system to slow or stop trains that missed signals or exceeded speed limits. Back then, the technology didnt exi
31、st. Today digital communications combined with GPS can monitor train locations and speeds, talk to trains and automatically take charge when a train needs to be slowed. About a third of train accidents from 2000 to 2009 were caused by human error, including cases when an engineer fell asleep or beca
32、me distracted.It took the horrific 2008 collision in California to finally get Congress attention. A Metrolink passenger train operator was texting, ran through a stop signal and collided with a freight train. The 25 deaths and 135 injuries pushed lawmakers to mandate that “positive train control“ t
33、echnology be installed on trains that carry passengers or hazardous materials by the end of 2015.The safety program is undoubtedly complex and costly. But theres one problem with the industrys insistence that the deadline couldnt be met, some railroads will meet it. If they can do it, why cant other
34、s? Some of the obstacles sound real. Commuter systems are often strapped for money. Congress has made available only one-fifth of what was supposed to be a 250 million fund to help with improvements.Even so, extending the deadline is no solution. It takes the pressure off the delinquents and is unfa
35、ir to the railroads that have complied. Accidents happen. But this one was preventable. So is the next one, but only if the railroads act.（分数：20.00）(1).What is the direct cause for Sundays accident? A.Over-speeding. B.Braking systems failed. C.The driver was sleeping. D.Poor safety technology.（分数：4.
36、00）A.B.C.D.(2).Why did so many railroads fail to install the automated braking systems? A.They couldnt afford them. B.There is still some time before the deadline. C.They thought it is unnecessary to install them. D.The possible accidents dont deserve the price they would pay.（分数：4.00）A.B.C.D.(3).Th
37、e functions of an automated backup system do NOT include that _. A.it can stop the train B.it can substitute with the driver C.it can remind the driver of the possible risks D.it can take charge if the train exceed the speed limit（分数：4.00）A.B.C.D.(4).What can be inferred from the last 2 paragraphs?
38、A.The safety program has collected enough funds. B.The local railroads are satisfied with the deadline. C.Congress will invest 50 million to the safety program. D.All of the railroads will have met the requirements by the deadline.（分数：4.00）A.B.C.D.(5).Which of the following can best summarize the te
39、xt? A.Accidents call for safety program for commuter systems. B.An automated system will prevent accidents effectively. C.Human errors are to blame for Sundays tragedy. D.The more we do, the less accident there will be.（分数：4.00）A.B.C.D.六、BText 4/B(总题数：1，分数：20.00)Nelson Mandela, the remarkable South
40、African who passed away on Thursday at 95, has made a great contribution to the world, especially to his motherland. Mandela led his people to freedom, ending the apartheid rule of South Africas brutal white-minority regime. But neither of those men, nor the others mentioned here, was put to such an
41、 extraordinary personal test.All you need to know to grasp the uniqueness of Mandela is this: he spent 27 years in prison, most of them in solitary confinement pounding rocks at the notorious Robben Island prison. He was given no hope and allowed little contact with the outside world. Yet instead of
42、 yielding to his plightor betraying his cause by speaking a few words that could have set him freehe persevered, leading in absentia against all odds and emerging victories.At his moment of triumph, with the presidency of South Africa in his hands, he sought not revenge for all that had been done to
43、 him but racial peace for his people, black or white, which incredibly he achieved. Such is the power of historys few truly great leaders and the examples they set. If Mandela could suffer as he did without seeking vengeance, then how could others do any less? And how could the nations fearful and s
44、uspicious white minority turn away the olive branch?Whether Mandelas legacy can endure remains an open question. Unlike the United States at its founding, South Africa has not been blessed with a succession of great leaders. Since Mandelas retirement in 1999, the presidency has been held by a succes
45、sion of lackluster men, and so the deep problems left behind by apartheid have festered. Crime and illiteracy are rampant, as is corruption. The unemployment rate is 25%, and far worse among the young. Life expectancy, barely over 50 years, is among the worlds lowest.As long as Mandela survived, eve
46、n with his capacity ravaged by his age and the harshness of his life, the simmering South African cauldron could not bubble over. No one dared upset their beloved Madiba.Perhaps that cannot last. What South Africa needs, like so many other strife-torn nations, is another Mandela. But such leaders ar
47、e the rarest of things. But they are remembered, admired to the extent that they are emulated, their impact lives on. No one will soon forget Nelson Mandela, if not the greatest man of the 20th century, certainly the most extraordinary.（分数：20.00）(1).Based on the first 2 paragraphs, which of the foll
48、owing is true? A.Mandela submitted himself to difficulty. B.One third of Mandelas life was spent in prison. C.Mandela hasnt finished the apartheid in South Africa. D.Mandela bears no revenge against those who have tortured him.（分数：4.00）A.B.C.D.(2).Which of the following can NOT be classified as the
49、uniqueness of Mandela? A.He didnt surrender himself to plight. B.He has been prisoned in Robben Island for 27 years. C.He could contact with the outside world at that time. D.He didnt give away his cause although in great difficulty.（分数：4.00）A.B.C.D.(3).After he took office, _. A.the white-minority fled away soon B.the white-minority was suppressed
