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Antidepressant(抗忧郁)drugs such as Prozac were viewed in the early 1900's as wonder pills that would remove depressive blues for good. But in the past five years, growing scientific evidence has shown these drugs work for only a minority of people. And now a research journal says that these antidepressants can make many patients' depression worse. This alarming suggestion centres on the very chemical that is targeted by antidepressants-serotonin(血清素). Drugs such as Prozac are known as selective serotonin re-uptake inhibitors(or SSRIs). Their aim is to increase the level of this  “feel-good” chemical in the brain.
But the new research, published in the journal Frontiers In Evolutionary Psychology, points out that serotonin is like a chemical Swiss Army knife, performing a very wide range of jobs in the brain and body. And when we start changing serotonin levels purposely, it may cause a wide range of unwanted effects. These can include digestive problems and even early deaths in older people, according to the study's lead researcher Paul Andrews. “ We need to be much more cautious about use of these drugs,” says Andrews, an assistant professor of evolutionary psychology at McMaster University in Ontario, Canada.
Previous research has suggested that the drugs provide little benefit for most people with mild depression, and actively help only a few of the most severely depressed. Famous psychologist Irving Kirsch has found that for many patients, SSRIs are no more effective than a placebo pill. A research in 2010 on Danish children found a small, but significant, increase in the risk of heart problems among babies whose mothers had used SSRIs in early pregnancy. The key to understanding these side-effects is serotonin, says Andrews. Serotonin is also the reason why patients can often end up feeling still more depressed after they have finished a course of SSRI drugs. He argues that SSRI antidepressants disturb the brain, leaving the patient an even greater depression than before.
“After long use, when a patient stops taking SSRIs, the brain will lower its levels of serotonin production,” he says, adding that it also changes the way receptors in the brain respond to serotonin, making the brain less sensitive to the chemical. These changes are believed to be temporary, but studies indicate that the effects may continue for up to two years.
Most disturbingly of all, Andrews' review features three recent studies which, he says , show that elderly antidepressant users are more likely to die earlier than non-users, even after taking other important variables into account. One study, published in the British Medical Journal last year, found patients given SSRIs were more than 4 per cent more likely to die in the next year than those not on the drugs.
“Serotonin is an ancient chemical,” says Andrews. “It is regulating many different processes, and when you disturb these things, you can expect that it is going to cause some harm.”
Stafford Lightman, professor of medicine at the University of Bristol, and a leading UK expert in brain chemicals and hormones, says Andrews’ review highlights some important problems, yet it should also be taken with a pinch of salt. “This report is doing the opposite of what drug companies do,” he says. “Drug companies selectively present all the positives in their research, while this search selectively presents all the negatives that can be found. Nevertheless, Andrews' study is useful in that it is always worth pointing out that there is a downside to any medicine. ” Professor Lightman adds that there is still a great deal we don't know about SSRIs-not least what they actually do in our brains.
When it comes to understanding why the drugs work only for a limited part of patients, U.S.  scientists think they might now have the answer. They think that in many depressed patients, it’s not only the lack of feel-good serotonin causing their depression, but also a failure in the area of the brain that produces new cells throughout our lives. This area, the hippocampus, is also responsible for regulating mood and memory. Research suggests that in patients whose hippocampus has lost the ability to produce new cells, SSRIs do not bring any benefit.
小题1:According to paragraph 2, serotonin, like a chemical Swiss Army knife, can             .
A.make many patients' depression worse
B.cause a wide range of unwanted effects
C.affect human body and brain in various ways
D.provide little benefit for most depressed people
小题2:In Stafford Lightman's opinion,                    .
A.drug companies don't know the negative effect of antidepressants
B.Andrews focused on different things from the drug companies
C.scientists have found what SSRIs do in the brain
D.Andrews' research has no medical value
小题3:Which of the following is TRUE about SSRIs?
A.They are used to increase the “feel-good” medical in the brain.
B.They can work even when the hippocampus can't produce new cells.
C.They create a risk of heart problems in pregnant women.
D.They are responsible for controlling mood and memory.
小题4:What is the text mainly about?
A.The aim of drug companies
B.The function of SSRIs
C.The side-effects of antidepressants
D.The cause of depression

小题1:C
小题2:B
小题3:A
小题4:C

试题分析:抗忧郁的药物如Prozac在二十世纪初期被认为是灵丹妙药,能让人的抑郁心情变好。但是在近五年间,不断增加的科学证据表明这些药物只对一小部分人有效, 而且使许多病人的抑郁症更严重。这类抗抑郁的药物在很多方面都有不容忽视的副作用。如记忆力减退、药物依赖性、早亡等等。
小题1:细节理解题。根据第二段的第一句话的意思(一项新的研究指出血清素就像一个化学的瑞士军刀一样,对人的大脑和身体都有影响。)判断选C。
小题2:细节理解题。根据第七段的意思(Stafford Lightman说:Andrew的观点指出了一些重要的问题。但是还不够。这个报告和药物公司做的相反,药物公司只说好处,而Andrew说出了药物的副作用。)判断Andrew和药物公司的关注点不同。故选B。
小题3:推理判断题。SSRIs的副作用有:对严重绝望的一些人有效,病情轻微的人几乎没什么好处。而且有依赖性。停药后病情会加重。丹麦的孩子中,其母亲怀孕早期用过此药的心脏病的发病率增加了。还会导致年老的人早亡。使人们不能再生产新的细胞,而这一区域还负责调节情绪和记忆。根据第一段最后一句的意思(这些药物旨在增加大脑中“感觉良好”的物质的量。)判断,选A。
小题4:主题归纳题。根据第一段的大意(近五年的科学证据表明:抗抑郁的药只对一小部分人有效, 而且使许多病人的抑郁症更严重。)判断,文章主要讲了对治疗忧郁症的药的副作用的新发现。故选C。
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科目:高中英语 来源:不详 题型:阅读理解

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科目:高中英语 来源:不详 题型:阅读理解

When people first walked across the Bering Land Bridge thousands of years ago, dogs were by their sides, according to a study published in the journal Science.
Robert Wayne of the University of California, Los Angeles, and Jennifer Leonard of the Smithsonian Institute, used DNA material—some of it unearthed by miners in Alaska—to conclude that today’s domestic dog originated in Asia and accompanied the first humans to the New World about 10,000 to 15,000 years ago. Wayne suggests that man’s best friend may have enabled the tough journey from Asia into North America. “Dogs may have been the reason people made it across the land bridge,” said Wayne. “They can pull things, carry things, defend you from fierce animals, and they’re useful to eat.”
Researchers have agreed that today’s dog is the result of the domestication(驯化) of wolves thousands of years ago. Before this recent study, a common thought about the precise origin of North America’s domestic dog was that Natives domesticated local wolves, the descendents(后代) of which now live with people in Alaska, Canada, and the Lower 48.
Dog remains from a Fairbanks-area gold mine helped the scientists reach their conclusion. Leonard, an evolutionary biologist, collected DNA from 11 bones of ancient dogs that were locked in permafrost(永冻层) until Fairbanks miners uncovered them in the 1920s. The miners donated the preserved bones to the American Museum of Natural History in New York City, where they remained untouched for more than 70 years. After borrowing the bones from the museum, Leonard and her colleagues used radiocarbon techniques to find the age of the Alaska dogs. They found the dogs all lived between the years of 1450 and 1675 A.D., before Vitus Bering and Aleksey Chirikov who were the first known Europeans to view Alaska in 1741. The bones of dogs that wandered the Fairbanks area centuries ago should therefore be the remains of “pure native American dogs,” Leonard said. The DNA of the Fairbanks dogs would also expose whether they were the descendents of wolves from North America.
Along with the Fairbanks samples, the researchers collected DNA from bones of 37 dog specimens(标本) from Mexico, Peru, and Bolivia that existed before the arrival of Columbus. In the case of both the Alaska dogs and the dogs from Latin America, the researchers found that they shared the most genetic material with gray wolves of Europe and Asia. This supports the idea of domestic dogs entering the New World with the first human explorers who wandered east over the land bridge.
Leonard and Wayne’s study suggests that dogs joined the first humans that made the adventure across the Bering Land Bridge to slowly populate the Americas. Wayne thinks the dogs that made the trip must have provided some excellent service to their human companions or they would not have been brought along. “Dogs must have been useful because they were expensive to keep,” Wayne said. “They didn’t feed on mice; they fed on meat, which was a very guarded resource.”
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A.leftover foodB.animal waste
C.dead bodiesD.living environment
小题2:According to the study described in Paragraph 4, we can learn that ______.
A.ancient dogs entered North America between 1450 and 1675 AD
B.the 11 bones of ancient dogs are not from native American dogs
C.the bones discovered by the gold miners were from North American wolves
D.the bones studied were not from dogs brought into North America by Europeans
小题3:What can we know from the passage?
A.Native Americans domesticated local wolves into dogs.
B.Scientists discovered some ancient dog remains in 1920s.
C.Latin America’s dogs are different from North America’s in genes.
D.Ancient dogs entered North America across the Bering Land Bridge.
小题4:The first humans into the New World brought dogs along with them because ______.
A.dogs fed on miceB.dogs were easy to keep
C.dogs helped protect their resourcesD.dogs could provide excellent service
小题5:What does the passage mainly talk about ______.
A.the origin of the North American dogs
B.the DNA study of ancient dogs in America
C.the reasons why early people entered America
D.the difference between Asian and American dogs

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