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(馴化) 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(永凍層) 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(標(biāo)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.”
小題1: The underlined word “remains” is closed in meaning to ______.
A．leftover foodB．a(chǎn)nimal waste
C．dead bodiesD．living environment
小題2:According to the study described in Paragraph 4, we can learn that ______.
A．a(chǎn)ncient 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
小題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.
小題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
小題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

小題1:C
小題2:D
小題3:D
小題4:D
小題5:A

試題分析：本文是科普性文章。說(shuō)明了在幾千年前狗陪同人們一起跨過(guò)白令大陸橋進(jìn)入北美大陸，并且在此繁殖起來(lái)。而通過(guò)檢測(cè)發(fā)掘出的狗骨頭的DNA也證實(shí)了這一點(diǎn)。
小題1:C 詞意猜測(cè)題。根據(jù)第四段第二句話“Leonard, an evolutionary biologist, collected DNA from 11 bones of ancient dogs that were locked in permafrost(永凍層)”說(shuō)明是在冰凍層發(fā)現(xiàn)的狗的骨頭，所以remain應(yīng)該是尸體。C選項(xiàng)正確。
小題2:D細(xì)節(jié)題。根據(jù)“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..”判斷可知被研究的骨頭不是歐洲人帶到北美來(lái)的狗的骨頭。所以D項(xiàng)正確。
小題3:D細(xì)節(jié)題。根據(jù)第一段“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.”所以D選項(xiàng)正確。
小題4:D 細(xì)節(jié)題。根據(jù)第二段“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.”這些都說(shuō)明了人們之所以帶著狗，是因?yàn)樗鼈兡転槿藗兲峁┓⻊?wù)，由用處。所以D正確。
小題5:A推理題。文章第一段提到狗和人們一同跨過(guò)the Bering Land Bridge，第二三四五段研究狗的DNA“ to conclude that today’s domestic dog originated in Asia”，“Researchers have agreed that today’s dog is the result of the domestication(馴化) of wolves thousands of years ago”所以文章中心是談?wù)摴返钠鹪础?/div>
練習(xí)冊(cè)系列答案
相關(guān)習(xí)題

科目：高中英語(yǔ) 來(lái)源：不詳 題型：閱讀理解

Antidepressant（抗憂郁）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.
小題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．a(chǎn)ffect human body and brain in various ways
D．provide little benefit for most depressed people
小題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
小題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.
小題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

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源：不詳 題型：閱讀理解

It had been a difficult move. I’d left my family and friends in Indiana, the beloved state where I’d lived most of my life. My new home in Florida was thousands of miles away from anything I knew. It was hot—all the time. Jobs were hard to come by, but I was up for almost any challenge.
At last, I taught in a special school where students have severe learning and behavioral difficulties.
Another teacher and I had spent weeks teaching the children appropriate behavior for public outings. Unexpectedly, only a few students, including Kyle, had not earned the privilege of going. He was determined to make his disappointment known.
In the corridor(走廊) between classrooms, he began screaming, cursing, spitting, and swinging at anything within striking distance. Once his outburst died down, he did what he’d done when he was angry at all his other schools, at home, even once at a juvenile detention(拘留)center. He ran.
People watched in disbelief as Kyle dashed straight into the heavy morning traffic in front of the school.
I heard someone shout, “Call the police!”
But I ran after him.
Kyle was at least a foot taller than me. And he was fast. His older brothers were track stars at the nearby high school. But I could run long distances without tiring. I would at least be able to keep him in my sight and know he was alive.
After several blocks of running directly into oncoming traffic, Kyle slowed his pace.
He took a sharp left. Standing next to a trash bin, Kyle bent over with his hands on his knees. I must have looked ridiculous. But his was not a look of fear. I saw his body relax. He did not attempt to run again. Kyle stood still and watched me approach. I had no idea what I was going to say or do, but I kept walking closer.
He opened his mouth to speak when a police car pulled up, abruptly filling the space between Kyle and me. The school principal and an officer got out. They spoke calmly to Kyle, who willingly climbed into the back of the vehicle. I couldn’t hear what was said, but I didn’t take my eyes off Kyle’s face, even as they drove away.
I couldn’t help but feel that I had failed him, that I should have done or said more, that I should have fixed the situation.
I shared my feelings with a speech therapist who was familiar with Kyle’s history. “No one ever ran after him before, Rachel,” she said. “No one. They just let him go.”
Things changed the day he ran and I ran after him, even though I didn’t have the right words, even though I wasn’t able to save him from the mess he was in. It was the day I didn’t throw my hands in the air and decide he was too fast, a waste of time and effort , a lost cause. It was the day my mere presence was enough to make a profound difference.
小題1:From the passage we know that _____.
A．the author left her family to Florida because jobs were hard to come by in Indiana.
B．students were allowed to go out after they passed some specific tests.
C．the author worked in a school where students were excellent.
D．no teacher had ever run after Kyle before except the author .
小題2:Which of the following description about Kyle is not true?
A．He had some behavioral difficulties and once moved from one detention to another.
B．He used to run out to let out his anger when he was in school,home or juvenile detention.
C．Different from his brothers, he learned in a special school while not a normal high school.
D．He was moved by his teacher who treated him with more patience and understanding.
小題3:Which is the correct order of the trace?
①He burst out when he knew he couldn’t go out.      ②I decided to run after him.
③Kyle stoppped beside a trash bin.                      ④A police car came and Kyle left with it.
⑤He rushed into the heavy morning traffic.       ⑥Kyle slowed his pace.
⑦I walked toward Kyle.
A．①⑤②⑥③⑦④B．①⑤②④⑥⑦③
C．⑤④②⑥③⑦①D．①②⑥⑦③④⑤
小題4:What is the best title of the passage?
A．Kyle, a Boy with Learning and Behavior Difficulties.
B．The Teacher Who Ran.
C．A School with Special Students.
D．A Terrible Conflict.

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源：不詳 題型：閱讀理解

This year’s Newsweek list of the top 100 high schools shows that today those with fewer students are rising.
Ten years ago, when the first Newsweek Top School List based on college-level test participation was published, only three of the top 100 schools had graduating classes smaller than 100 students. This year there are 22.
Fifty years ago, they were the latest thing in educational reform: big, modern high schools outside the cities with thousands of students. Big schools meant economic efficiency, a greater choice of courses, and better football teams. But only years later did we understand that it involved the difficulty of strengthening personal connections between teachers and students. SAT scores began dropping; on average, 30% of students did not complete high school in four years, a figure that rose to 50% in poor city neighborhoods. High schools for a variety of reasons seemed to have made little progress.
Size isn’t everything, but it does matter, and the past decade has seen a noticeable trend toward smaller schools. This has been partly due to the Bill and Melinda Gates Foundation, which has invested $1.8 billion in American high schools, helping to open about 1,000 small schools — most of them with about 400 kids, each with an average enrollment of only 150 students per grade. About 500 more are on the drawing board. Districts all over the country are taking notice, along with mayors in cities like New York, Chicago and San Diego. And most noticeable of all, there is the phenomenon of large urban and suburban high schools that have split up into smaller units of a few hundred.
Hillsdale High School in San Mateo, California, is one of those ranking No.423 — among the top 2% in the country. In 2003, Hillsdale remade itself into three “houses”. 300 students arriving ninth graders are randomly assigned to one of the houses, where they will keep the same four core subject teachers for two years before moving on to another for 11th and 12th grades. Teachers meet with students in groups of 25, five mornings a week, for open-ended discussions of everything from homework problems to bad Saturday-night dates. The advisers also meet with students privately and stay in touch with parents. Along with the new structure came the percentage of freshmen taking biology jumped from 17 to 95.”It was rough for some. But by senior year, two-thirds have moved up to physics,” says Jeff Gilbert. “Our kids are coming to school in part because they know there are adults here who know them and care for them.”
But not all schools show advances after downsizing, and it remains to be seen whether smaller schools will be a cure-all solution.
Ranking schools is always controversial. Over the years this system has been criticized for its simplicity — list of top U.S. high schools was made merely according to the proportion of students taking college-level exams. This year a group of 38 superintendents (地區(qū)教育主管) from five states wrote to ask that their schools should be excluded from the calculation. “It is impossible to know which high schools are ‘the best’ in the nation,” their letter read. “Determining whether different schools do or don’t offer a high quality of education requires a look at many different measures, including students’ overall academic accomplishments, their later performance in college, and taking into consideration the unique needs of their communities.”
小題1:What can we learn about the schools sponsored by the Bill and Melinda Gates Foundation?
A．They are often located in poor neighborhoods.
B．They are popular with high-achieving students.
C．They are mostly small in size.
D．Another 150 schools invested by the Foundation are planned to be set up.
小題2:According to Jeff Gilbert, the classes at Hillsdale were set up so that students could ______.
A．tell their teachers what they did on weekends
B．experience a great deal of pleasure in learning
C．maintain closer relationships with their teachers
D．deal with the demanding biology and physics courses
小題3:Newsweek ranks high schools according to ______.
A．their students’ academic achievement
B．the number of their students admitted to college
C．the size and number of their graduating classes
D．their college-level test participation
小題4:What attitude does the author have towards the present trend in high school education?
A．Subjective.B．Objective.C．Indifferent.D．Disapproving.
小題5:Which of the following can be the best title for the passage?
A．Providing Good Education for Baby Boomers
B．Top School List Winning National Support
C．Small Schools Rising in popularity
D．Students Meeting Higher Academic Standards

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源：不詳 題型：閱讀理解

Rae and Bruce Hostetler not only work very hard,they also relax just as well. Numerous vacations help the couple to maintain their health and emotional well-being一and it’s no surprise to health care professionals.
“Rest, relaxation, and stress reduction are very important for people’s well-being and health. This can be accomplished through daily activities, such as exercise and meditation, but vacation is an important part of this as well,” said primary care physician Natasha Withers from One Medical Group in New York. Withers lists a decreased risk of heart disease and improved reaction time as some of the benefits from taking some time off. “We also know that the mind is very powerful and can help with healing, so a rested, relaxed mind is able to help the body heal better,” said Withers.
Psychologists confirm the value of vacations for the mind. “The impact that taking a vacation has on one’s mental health is great,” said Francine Lederer, a clinical psychologist in Los Angeles who specializes in stress and relationship management. “Most people have better life perspective and are more motivated to achieve their goals after a vacation, even if it is a 24- hour time-out.” The trips could be good for their health, good for their family and good for their businesses.
The online travel agency Expedia conducted a survey about vacation time in 2010, and according to their data the average American earned 18 vacation days一but only used 14 of them. France topped the list, with the average worker earning 37 vacation days and using all but two of them. Americans’ responses may not be surprising in a culture where long hours on the job often are valued, but that’s not always good for the individual, the family or the employer.
Psychologists have also found that people who don’t take enough time to relax may find it harder to relax in the future. “Without time and opportunity to do this, the nerve connections that produce feelings of calm and peacefulness become weaker, making it actually more difficult to shift into less-stressed states,” Mulhem said.
小題1:How did the author introduce the topic of the text?
A．By making comparisons.B．By giving an example.
C．By raising questions.D．By providing data.
小題2:Expedia’s survey shows that Americans _____.
A．dislike family gatherings
B．have the shortest vacation
C．enjoy as many vacations as the French
D．think much of spending long hours on the job
小題3:What can be inferred from the last paragraph?
A．One should never wait to relax.
B．Work and rest go against each other.
C．Time and opportunity wait for no man.
D．A relaxed mind determines everything.

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源：不詳 題型：閱讀理解

When someone says “SHARK” most people think of a big, toothy, underwater animal; basically we are imagining a Great White. In fact sharks come in all shapes, sizes and even colors! Follow me please; I’d like to show you a very special small shark commonly known as horn sharks, only found in the coastal waters of north-west North America.
Look at this shark, and you can easily see the horns on it and you will know the reason why it is called the horn shark is that it has the broad, flattened head and two large horn-like spines(脊椎) found behind its eyes and makes it one of the hardiest of all shark species. What makes it unique is that as its enemy attempts to swallow it, the spines on its back will stick into the enemy’s mouth and give a good chance for it to get away.
The horn shark is brown in color with black spots all over its body. The adults can reach up to a length of 4 feet and weigh up to 10 kg. An interesting fact about the horn shark is that it has five gills(鰓). The horn shark is a clumsy swimmer using its flexible pectoral fins(胸鰭)to push itself along the bottom of the ocean. The maximum distance that has ever been recorded for a horn shark to have traveled out from its habitat is 10 miles.
Today, as so little is known about its population off the Californian coast, they have been listed as being “Data Deficient” in the World Conservation Union. The horn shark is being threatened both by water pollution and commercial fishing in the area. Though they are not among those sea creatures hunted primarily for food, but they often get caught as a by-catch in fishing expeditions.
小題1:The horn shark gets its name for______.
A．its small sizeB．its large eyes
C．its two large spinesD．its brown color with spots
小題2:How is paragraph 3 mainly developed?
A．By giving descriptionsB．By following time order
C．By analyzing causesD．By making comparisons
小題3:Which factors contribute to the horn shark’s being on the “Data Deficient” list?
①That people like hunting them for pets       ②That people fish them for fun
③Water pollution off the coast               ④Knowing little about them
A．①②B．②③C．①④D．③④
小題4: According to the passage, all of the following are unique to the horn shark EXCEPT that_____.
A．it doesn’t travel far
B．it is good at swimming
C．its spines can be used to attack the enemy and escape
D．it is only found in the coastal waters of north-west North America

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源：不詳 題型：閱讀理解

The rat is named Lola and she’s at the top of her class of risk-running animals being trained to smell out landmines (地雷) in Colombia, home to the world’s highest number of mine-related deaths and injuries last year. Of the victims, many are children who died in the accidents while walking to school or playing in the countryside.
The smartest rat among the first six that the government is teaching to locate landmines equipment planted by rebels(叛亂者) has a 90 percent success rate in locating landmines material in her lab training.
Police animal trainers, tired of seeing their landmines-smelling dogs blown up by stepping on mines, hope the white-furred, pink-eyed creature will lead her classmates through coming open field tests and then into the country mine fields before the end of the year. It takes about 400 grams of pressure to detonate (引爆) a mine while Lola only weighs about 220 grams. “The dogs can easily set off the landmines, sometimes killing people nearby,” they said.
Police animal trainer Jose Pineda says that rats have more sensitive noses than dogs, which should allow them to better smell out mines in difficult terrain (地形).
Plus, it takes the police about six months to train mine-smelling dogs. Training the rats is expected to take about half that time once the program is established.
Trainers think that they are much smarter than the dogs. The second-best scorer in the laboratory is Lucrecia, with an 83 percent success rate. Males, such as one named   Runcho, have fallen behind until now but may do better in the coming field tests. Pineda said that the next step of training will present new challenges to the rats as they are sure to meet distractions (分心的事) in the open.
小題1:What do the underlined words “the accidents” in the first paragraph mean?
A．Children were shot while playing outside.
B．A buried landmine was walked on and set off.
C．A rebel blew up a landmine and killed children.
D．Children got hurt in traffic accidents on the way to school.
小題2:Which of the following is NOT a reason why rats are chosen to find buried landmines?
A．They have a good sense of smell.
B．They are too light to set off buried landmines.
C．They can smell all kinds of explosive materials.
D．They cost people less time in terms of training
小題3:What can we learn from the last paragraph?
A．Rats will perform as well in the open air as in the lab.
B．Until now, female rats are better than the male ones.
C．Trainers should have chosen only female rats for the program.
D．Because they are foolish, dogs are not preferred for the program.
小題4:What would be the best title for the passage?
A．Dogs Bring Peace to the People in Colombia
B．Colombia Develops a New Way to Reduce Deaths
C．Buried Landmines are a Great Danger to Colombians
D．Colombian Police Train Rats to Sniff Out Landmines

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源：不詳 題型：閱讀理解



If a diver surfaces too quickly, he may suffer the bends. Nitrogen (氮) dissolved (溶解) in his blood is suddenly liberated by the reduction of pressure. The consequence, if the bubbles (氣泡) accumulate in a joint, is sharp pain and a bent body—thus the name. If the bubbles form in his lungs or his brain, the consequence can be death.
Other air-breathing animals also suffer this decompression (減壓) sickness if they surface too fast: whales, for example. And so, long ago, did ichthyosaurs. That these ancient sea animals got the bends can be seen from their bones. If bubbles of nitrogen form inside the bone they can cut off its blood supply. This kills the cells in the bone, and consequently weakens it, sometimes to the point of collapse. Fossil (化石) bones that have caved in on themselves are thus a sign that the animal once had the bends.
Bruce Rothschild of the University of Kansas knew all this when he began a study of ichthyosaur bones to find out how widespread the problem was in the past. What he particularly wanted to investigate was how ichthyosaurs adapted to the problem of decompression over the 150 million years. To this end, he and his colleagues traveled the world’s natural-history museums, looking at hundreds of ichthyosaurs from the Triassic period and from the later Jurassic and Cretaceous periods.
When he started, he assumed that signs of the bends would be rarer in younger fossils, reflecting their gradual evolution of measures to deal with decompression. Instead, he was astonished to discover the opposite. More than 15% of Jurassic and Cretaceous ichthyosaurs had suffered the bends before they died, but not a single Triassic specimen (標(biāo)本) showed evidence of that sort of injury.
If ichthyosaurs did evolve an anti-decompression means, they clearly did so quickly—and, most strangely, they lost it afterwards. But that is not what Dr Rothschild thinks happened. He suspects it was evolution in other animals that caused the change.
Whales that suffer the bends often do so because they have surfaced to escape a predator (捕食動(dòng)物) such as a large shark. One of the features of Jurassic oceans was an abundance of large sharks and crocodiles, both of which were fond of ichthyosaur lunches. Triassic oceans, by contrast, were mercifully shark- and crocodile-free. In the Triassic, then, ichthyosaurs were top of the food chain. In the Jurassic and Cretaceous, they were prey (獵物) as well as predator—and often had to make a speedy exit as a result.
小題1:Which of the following is a typical symptom of the bends?
A．A twisted body.
B．A gradual decrease in blood supply.
C．A sudden release of nitrogen in blood.
D．A drop in blood pressure.
小題2:The purpose of Rothschild’s study is to see ______.
A．how often ichthyosaurs caught the bends
B．how ichthyosaurs adapted to decompression
C．why ichthyosaurs bent their bodies
D．when ichthyosaurs broke their bones
小題3:Rothschild’s finding stated in Paragraph 4 ______.
A．confirmed his assumptionB．speeded up his research process
C．disagreed with his assumptionD．changed his research objectives
小題4:Rothschild might have concluded that ichthyosaurs ______.
A．failed to evolve an anti-decompression means
B．gradually developed measures against the bends
C．died out because of large sharks and crocodiles
D．evolved an anti-decompression means but soon lost it

查看答案和解析>>

科目：高中英語(yǔ) 來(lái)源：不詳 題型：閱讀理解

Laws that would have ensured pupils from five to 16 received a full financial education got lost in the ‘wash up’. An application is calling on the next government to bring it back.
　At school the children are taught to add up and subtract(減法) but, extraordinarily, are not routinely shown how to open a bank account — let alone how to manage their finances in an increasingly complex and demanding world.
　Today the parenting website Mumsnet and the consumer campaigner Martin Lewis have joined forces to launch an online application to make financial education a compulsory element of the school curriculum in England. Children from five to 16 should be taught about everything from pocket money to pensions, they say. And that was exactly the plan preserved in the Children, Schools and Families bill that was shelved by the government in the so-called “wash-up” earlier this month — the rush to legislation before parliament was dismissed. Consumer and parent groups believe financial education has always been one of the most frustrating omissions of the curriculum.
　As the Personal Finance Education Group (Pfeg) points out, the good habits of young children do not last long. Over 75% of seven- to 11-year-olds are savers but by the time they get to 17, over half of them are in debt to family and friends. By this age, 26% see a credit card or overdraft(透支) as a way of extending their spending power. Pfeg predicts that these young people will “find it much harder to avoid the serious unexpected dangers that have befallen many of their parents' generation unless they receive good quality financial education while at school.”
　The UK has been in the worst financial recession(衰退)for generations. It does seem odd that — unless parents step in — young people are left in the dark until they are cruelly introduced to the world of debt when they turn up at university. In a recent poll of over 8,000 people, 97% supported financial education in schools, while 3% said it was a job for parents.
小題1:The passage is mainly about _____________.
A．how to manage school lessonsB． teaching young people about money　
C．how to deal with the financial crisisD．teaching students how to study effectively
小題2:It can be inferred from the first two paragraphs that __________.
A．laws on financial education have been effectively carried out
B．pupils should not be taught to add up and subtract
C．students have been taught to manage their finances
D．the author complains about the school education
小題3:The website and the consumer campaigner joined to _________.
A．instruct the pupils to donate their pocket money
B．promote the connection of schools and families
C．a(chǎn)sk the government to dismiss the parliament
D．a(chǎn)ppeal for the curriculum of financial education
小題4:A poll is mentioned to ___________.
A．show the seriousness of the financial recession
B．stress the necessity of the curriculum reform
C．make the readers aware of burden of the parents
D．illustrate some people are strongly against the proposal

查看答案和解析>>

同步練習(xí)冊(cè)答案