Plants may not have eyes and ears，but they can recognize their siblings (兄弟姐妹)，and researchers at the University of Delaware have discovered how.The ID system lies in the roots and the chemical signals they secrete (分泌)．
Canadian researchers published that sea rocket，a common seashore plant，can recognize its siblings.Susan Dudley observed that when siblings are grown next to each other in the soil，they “play nice” and don’t send out more roots to compete.However，the moment one of the plants is thrown in with strangers，it begins competing with them by rapidly growing more roots to take up the water and mineral nutrients in the soil.
After reading Dudley’s study，Bais decided to find the method behind the sibling recognition.Working in his laboratory，Bais and his doctoral student Meredith Biedrzycki set up a study with wild populations of Arabidopsis thaliana.In a series of experiments，young seedlings were exposed to liquid media containing the root secretions from siblings，from strangers，or only their own secretions.The length of the longest lateral (侧面的) root was measured.The exposure of plants to the root secretions of strangers induced (引诱) greater lateral root formation than exposure of plants to sibling secretions.Strangers planted next to each other are often shorter，because so much of their energy is directed at root growth.Because siblings aren’t competing against each other，their roots are often much shallower (浅的)．
Biedrzycki did the painstaking laboratory research，observing more than 3,000 plants involved in the study every day for seven continuous days and documenting the root patterns.“Arabidopsis roots are nearly translucent (半透明的) when they are young and were also twisted when I removed them from plates，”Biedrzycki notes.“This manuscript (手稿) is very important for my research since the focus of my thesis project is understanding the biochemical ways behind root secretions.”
The research also may have implications for the home gardener.“Often we’ll put plants in the ground next to each other and when they don’t do well，we blame the local garden center where we bought them or we attribute their failure to a germ，”Bais says.“But maybe there’s more to it than that.”Which of the following would be the best title for this passage?
| A．A Great Biology Researcher |
| B．Plants Recognize Their Siblings |
| C．Plants’ Roots and Secretions |
| D．A Research on Plants |
What encouraged Bais to study the sibling recognition?
| A．Sea rocket. |
| B．Plants’ sensing system. |
| C．Biedrzycki’s thesis project. |
| D．Dudley’s study. |
What does the underlined word “painstaking” in Paragraph 4 probably mean?
| A．Important. | B．Adventurous. |
| C．Careful. | D．Hardworking. |
What can we infer from the last paragraph?
| A．The local garden center should be blamed when plants can’t grow well. |
| B．The local garden center often sells low quality seeds to customers. |
| C．Plants in the home garden can’t grow well because of the germ and seeds. |
| D．Competing against strangers，plants in the home garden can’t grow well. |
Does a drink a day keep heart attacks away? Over the past 20 years, numerous studies have found that moderate alcohol consumption, say, one or two beers, glasses of wine or cocktails daily helps to prevent coronary heart disease. Last week a report in the New England Journal of Medicine added strong new evidence in support of that theory. More important, the work provided the first solid induction (归纳) of how alcohol works to protect the heart.
In the study, researchers from Boston’s Brigham and Women’s Hospital and Harvard Medical School compared the drinking habits of 340 men and women who had suffered recent heart attack with those of healthy people of the same age and sex. The scientists found that people who sip one to three drinks a day are about half as likely to suffer heart attacks as nondrinkers are. The apparent source of the protection: those who drank alcohol had higher blood levels of high density lipoproteins, the so-called good cholesterol, which is known to prevent heart disease.
As evidence has mounted, some doctors have begun recommending a daily drink for patients of heart diseases. But most physicians are not ready to recommend a regular happy hour for everyone. The risks of teetotalling (绝对戒酒) are nothing compared with the dangers of too much alcohol, including high blood pressure, strokes and liver troubles—not to mention violent behaviour and traffic accidents. Moreover, some studies suggest that even moderate drinking may increase the incidence of breast and colon cancer. Until there is evidence that the benefits of a daily dose of alcohol outweigh the risks, most people won’t be able to take a doctor’s prescription to the neighbourhood bar or liquor store.The medical article quoted in the first paragraph indicates .
A. the way in which alcohol can help the heart
B. how a couple of cocktails daily can stop heart problems
C. why alcoholic drinks are dangerous to one’s health
that reports on the advantages of alcohol were misledExperiments showed that nondrinkers had __________.
| A．larger amounts of good cholesterol | B．smaller amounts of good cholesterol |
| C．higher blood pressure | D．lower blood pressure |
According to the passage, moderate drinking .
| A．is recommended by most doctors for heart patients |
| B．should be allowed on prescription |
| C．is still not medically advisable |
| D．is not related to liver problems |
The main theme of this passage is .
| A．the change in recent drinking habits |
| B．the connection between cancer and alcohol |
| C．whether moderate drinkers outlive nondrinkers |
| D．whether alcohol may be good for one’s health |
When we hear the words “college students”, we usually think of a young person between 18 and 22 years old. But in the U.S.A today, a college student often is much older. In fact, educators say in the next few years colleges and universities may have more older part-time students than traditional (传统的) full-time younger students.
Educators report a big increase in the number of Americans who attend college and university classes in the evening or at night or weekends. Most of them are older than 25 years old and more have full-time or part-time jobs. Many are in their thirties or forties.
Why are so many people deciding to spend their time and money in order to continue their education? Most are doing it because they believe more education will help them to get a better job. Some are industrial workers whose factories have closed. They are learning new skills to prepare for other kinds of work. Some of the part-time students are not pleased with the jobs they have. They are studying for new ones. Some have retired (退休) and are looking for new kinds of work. Two of every three of the students older than 35 are women. Many of them are returning to school after years of staying at home to care for children.
Are older students good students? Most teachers say yes. They say older students really want to learn. They ask difficult questions and are not pleased with simple answers. They often get high grades. It’s said that in the next few years _________________.
| A．students in colleges and universities will be much older |
| B． full-time students in colleges and universities will be even younger |
| C． American colleges and universities will take in part-time students equally |
| D． The number of older students will be greater than that of the younger ones |
Judge which of the following is not true according to the above passage.
| A．It’s reported that a large number of Americans attend college or universities classes in their spare time. |
| B． Most of them are over 25. |
| C． Most of them are without jobs. |
| D． The number of students in colleges and universities is reported to have gone up greatly. |
Why are so many people deciding to go on with their education? Because___________.
| A．Most of the Americans enjoy learning something new |
| B． Most of them believe: more education, better jobs |
| C． They have lost their jobs |
| D． They are tired of their jobs they have |
They often get high grades” means ____________.
| A．they rise to high grades easily |
| B． they often get very good marks (分数) |
| C． they are more likely to receive a master’s or a doctor’s degree upon graduation |
| D．they often win high prize |
What does the whole passage mainly tell us?
| A．Why does so many older students go to college in America. |
| B．What older students in college can learn. |
| C．Older students are mostly good students |
| D．Higher education can help you get a good job. |
American’s genius with high technology may have put men on the moon, but there is growing doubt about its ability to solve human problems closer to home.
In fact, a slight but significant change from purely technological solutions is already under way as scientists insist that answers to the world’s problems will not come from an attractive exhibition of electronics and machines. Instead, as they see it, solutions must develop from a better understanding of the humans that drive the system and from a fuller appreciation of the limits and potential(潜能) of the earth’s resources.
What this means is an increased emphasis on the life and earth sciences, on sociology, psychology, economics and even philosophy.
More and more of the best minds in science, particularly young researchers, are being drawn into these developing fields.
All this is not to say that technological creativity will not play a critical role in solving energy and food shortages, or that answers to environmental difficulties will not come from further advances in the same technologies that may have helped cause the problems.
Where the real challenge lies, in the view of the new generation of scientists, is in finding ways to produce goods and meet the world’s needs, using less of the raw materials that are becoming short. Which of the following would the author probably agree with?
| A．The environment crisis will not be solved unless we stop using virgin（原始）materials. |
| B．In scientific research, a higher priority（优先）should be given to understanding all living systems. |
| C．Exploration of outer space will finally lead to an improvement on human living conditions. |
| D．U. S. high-technology companies are welcoming this new change in scientific research. |
Which of the following best expresses the main idea?
| A．a growing number of Americans are doubtful about what high technology can do in solving the world’s problems. |
| B．Many scientists are beginning to believe that the better understanding of human beings will play a more decisive role in solving the world’s problems. |
| C．More and more young scientists are trying their best to find new ways to solve the world’s problems. |
| D．Technological creativity will still play a very important part in solving the world’s problems. |
Young scientists demand that in order to satisfy human needs ________.
| A．existing products be improved. |
| B．more complex machines and electronic equipment be designed. |
| C．ways be found to produce better goods using fewer raw materials. |
| D．any new invention and innovation be encouraged in technology |
In the passage “Human problems” or “world problems” refers mainly to ______.
| A．global food shortage | B．resources depletion（耗尽） |
| C．environmental pollution | D．all of the above |
The author states all the following CXCEPT that _______.
| A．the development of present techniques cannot provide any answers to today’s problems. |
| B．an increasing number of young scientists are taking a great interest in biological and social sciences. |
| C．many scientists have come to understand the limits of natural resources. |
| D．many scientists argue that high technology is something but not everything. |
My father had returned from his business visit to London when I came in, rather late, to supper. I could tell at once that he and my mother had been discussing something. In that half-playful, half-serious way I knew so well, he said, "How would you like to go to Eton?"
"You bet," I cried quickly catching the joke. Everyone knew it was the most expensive, the most famous of schools. You had to be entered at birth, if not before. Besides, even at 12 or 13, I understood my father. He disliked any form of showing off. He always knew his proper station in life, which was in the middle of the middle class, our house was medium-sized; he had avoided joining Royal Liverpool Golf Club and went to a smaller one instead; though once he had got a second-hand Rolls-Royce at a remarkably low price, he felt embarrassed driving it, and quickly changed it for an Austin 1100.
This could only be his delightful way of telling me that the whole boarding school idea was to be dropped. Alas! I should also have remembered that he had a liking for being different from everyone else, if it did not conflict with his fear of drawing attention to himself.
It seemed that he had happened to be talking to Graham Brown of the London office, a very nice fellow, and Graham had a friend who had just entered his boy at the school, and while he was in that part of the world he thought he might just as well phone them. I remember my eyes stinging(刺痛) and my hands shaking with the confusion of my feelings. There was excitement, at the heart of great sadness.
"Oh, he doesn’t want to go away," said my mother, "You shouldn’t go on like this.” “It’s up to him," said my father. "He can make up his own mind."The house the writer’s family lived in was ________.
| A．the best they could afford | B．right for their social position |
| C．for showing off | D．rather small |
His father sold his Roils-Royce because ________.
| A．it made him feel uneasy | B．it was too old to work well |
| C．it was too expensive to possess | D．it was too cheap |
The writer’s father enjoyed being different as long as ________.
| A．it drew attention to him | B．it didn’t bring him in arguments |
| C．it was understood as a joke | D．there was no danger of his showing off |
What was the writer’s reaction to the idea of going to Eton?
| A．He was very unhappy. | B．He didn’t believe it. |
| C．He was delighted. | D．He had mixed feelings. |
What was the writer’s reaction to the idea of going to boarding-school?
| A．He was very unhappy, | B．He had mixed feelings. |
| C．He was delighted, | D．He didn't believe it. |
People Born in Autumn Live Longer
People born in the autumn live longer than those born in the spring and are less likely to fall chronically ill when they are older, according to an Austrian scientist.
Using census（人口普查）data for more than one million people in Austria, Denmark and Australia, scientists at the Max Planck Institute in the northern German town of Rostock found the month of birth was related to life expectancy（预期寿命）over the age of 50. Seasonal differences in what mothers ate during pregnancy, and infections occurring at different times of the year could both have an impact on the health of a new-born baby and could influence its life expectancy in older age. “A mother giving birth in spring spends the last phase of her pregnancy in winter, when she will eat less vitamins than in summer,” said Gabriele Doblhammer, one of a team of scientists who carried out the research. “When she stops breast-feeding and starts giving her baby normal food, it’s in the hot weeks of summer when babies are prone (易于)to infections of the digestive system.” In Austria, adults born in autumn (October-December) lived about seven months longer than those born in spring (April-June), and in Denmark adults with birthdays in autumn outlived those born in spring by about four months. In the southern hemisphere, the picture was similar. Adults born in the Australian autumn—the European spring—lived about four months longer than those born in the Australian spring. The study focused on people born at the beginning of the 20th century, using death certificates and census data. Although nutrition at all times of the year has improved since then, the seasonal pattern persists, Doblhammer said.
But on the other hand, according to a study of more 40,000 people, those born in spring and summer report themselves luckier than those born in autumn or winter. Professor Richard Wise-man who led the research explained that the temperature at the time of birth might influence the development of the brain and seasonal factors make a difference as well.The underlined word “outlived” in the text probably means ________.
| A．lived out of | B．depended on |
| C．had a shorter life than | D．lived longer than |
The census data of the following countries is used for research EXCEPT _______.
| A．Germany. | B．Denmark. |
| C．Australia. | D．Austria. |
What’s the main idea of this text?
| A．Nutrition at all times of the year has improved since the beginning of the 20th century. |
| B．In Austria, adults born in autumn (October—December) lived about seven months longer than those born in spring (April—June). |
| C．People born in autumn live longer than those born in spring and are less likely to fall ill when they are older. |
| D．Babies are prone to infections of the digestive system. |
Which of the following is NOT true according to the text?
| A．Infections occurring at different times of the year influence the health of a new-born baby. |
| B．The study focused on people born in the late 20th century. |
| C．A mother giving birth in spring eats less vitamins during the last phase of her pregnancy in winter. |
| D．What mothers ate during pregnancy could have an impact on the babies’ life expectancy in older age. |
The right sentence of the following is ________.
| A．The month of birth was not related to life expectancy over the age of 50. |
| B．A mother giving birth in spring spends the last phase of her pregnancy in winter, eating more vitamins than in summer. |
| C．Stopping breast-feeding and starting giving babies normal food must make babies prone to get infected with the digestive system in the hot weeks of summer. |
| D．Adults born in the Australian autumn―the European spring―lived about four months longer than those born in the Australian spring. |
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