单选题If roundworms are removed from the soil and placed in a liquid, they thrash helplessly around. A. carelessly B. tirelessly C. powerlessly D. heartlessly

单选题BUS CCTV Predict Assaults CCTV security systems could soon spot an assault on a bus before it happens, according to a major research project. The system, part of which has already been tested in laboratory conditions, looks for suspicious behaviour associated with crime. It would be able to send live CCTV pictures to operation rooms, from where controllers would be able to intervene. The Queens University Belfast team say the software could make a significant impact on crime on transport. Although much of the work is currently at the theoretical stage, they predict that within five years their software will be able to profile people as they board a bus. The system would then compare who it thinks these people are, and what they are doing, with more general data on the bus's location, time of day and historic crime rates. Once it has sifted this data, it could be able to conclude whether someone is about to commit an assault and send live pictures to controllers. Dr Paul Miller, head of the research project, said the 15-strong team were still developing initial databases to identify an individual's gender and body shape. However, the team say the system goes further by then looking for recognised signs of an imminent criminal offence. These signs include someone moving seats shortly before an assault, groups closing in on a passenger sitting alone and people loitering on a double-decker's stairwell, or close to the driver's cab. The system would only alert a controller if the sum of all of these" atomic events" added up to the Drofile of a possible crime. "The system won't be able to say, 'this is an incident' —but it will be able to push that video stream to the top of the queue for security analysts [in a control room] to make a decision, "said Dr Miller." Ultimately, most of the events will be benign, with nothing going on. That's why you still need the human element. " Dr Miller said that laboratory tests on gender recognition, based on a database of 4,000 faces, had proved successful and the project would move into testing systems on buses over the next year. "Research shows crimes happen when there is an opportunity and no chance of payback," he said. "If a security analyst can directly communicate with the assailant, to tell them they are being watched, it will have a marked effect on the offender. Just one example of this actually happening can have a deterrent effect on the crime rate in an area. /

单选题The standards set four years ago in Seoul will be far below the athletes' capabilities now.A. capacitiesB. strengthsC. possibilitiesD. abilities

单选题Pushbike Danger Low speed bicycle crashes can badly injure—or even kill—children if they fall onto the ends of the handlebars (车把). So a team of engineers is redesigning it to make it safer. Kristy Arbogast, a bioengineer at the Children's Hospital of Philadelphia in Pennsylvania, began the project with her colleagues. The cases they reviewed about serious abdominal (腹部的) injuries in children in the past 30 years showed that more than a third were caused by bicycle accidents. "The task was to identify how the injuries occurred and come up with some countermeasures. " she says. By interviewing the children and their parents, Arbogast and her team were able to reconstruct many of the accidents and identified a common cause for serious injuries. They discovered that most cases occur when children hit an obstacle at slow speed, causing them to topple (摇摆) over. To maintain their balance the children turn the handlebars through 90 degrees—but their momentum (冲力) forces them into the end of the handlebars. The bike then falls over and the other end of the handlebars hits the ground, pushing it into their abdomen (腹部). The solution the group came up with is a handgrip (握柄) fitted with a spring and damping (减速) system. The spring absorbs up to 50 per cent of the forces transmitted (传递) through the handlebars in an impact. The group hopes to commercialize the device, which should add only a few dollars to the cost of a bike. "But our task has been one of education because up until now, bicycle manufacturers were unaware of the problem. " says Arbogast.

单选题Medicine Award Kicks off Nobel Prize Announcements Two scientists who have won praise for research into the growth of cancer cells could be candidates for the Nobel Prize in medicine when the 2008 winners are presented on Monday, kicking off six days of Nobel announcements. Australian-born U- S. citizen Elizabeth Blackburn and American Carol Greider have already won a series of medical honors for their enzyme research and experts say they could be among the front-runners for a Nobel. Only seven women have won the medicine prize since the first Nobel Prizes were handed out in 1901. The last female winner was U. S. researcher Linda Buck in 2004, who shared the prize with Richard Axel. Among the pair's possible rivals are Frenchman Pierre Chambon and Americans Ronald Evans and Elwood Jensen, who opened up the field of studying proteins called nuclear hormone receptors. As usual, the award committee is giving no hints about who is in the running before presenting its decision in a news conference at Stockholm's Karolinska Institute. Alfred Nobel, the Swede who invented dynamite, established the prizes in his will in the categories of medicine, physics, chemistry, literature and peace. The economics prize is technically not a Nobel but a 1968 creation of Sweden's central bank. Nobel left few instructions on how to select-winners, but medicine winners are typically awarded for a specific breakthrough rather than a body of research. Hans Jornvall, secretary of the medicine prize committee, said the 10 million kronor (US$1.3 million) prize encourages groundbreaking research but he did not think winning it was the primary goal for scientists. "Individual researchers probably don't look at themselves as potential Nobel Prize winners when they're at work," Jornvall told The Associated Press. "They get their kicks from their research and their interest in how life functions. " In 2006, Blackburn, of the University of California, "San Francisco, and Greider, of Johns Hopkins University in Baltimore, shared the Lasker prize for basic medical research with Jack Szostak of Harvard Medical School. Their work set the stage for research suggesting that cancer cells use telomerase to sustain their uncontrolled growth

单选题The soldier displayed remarkable courage in the battle.

单选题{{B}}第三篇{{/B}} Where Have All the Bees Gone? Scientists who study insects have a real mystery on their hands. All across the country, honeybees are leaving their hives and never returning. Researchers call this phenomenon colony-collapse (瓦解) disorder. According to surveys of beekeepers (养蜂人) across the country, 25 to 40 percent of the honeybees in the United States have vanished from their hives (麻疹) since last fall. So far, no one can explain why. Colony collapse is a serious concern because bees play an important role in the production of about one-third of the foods we eat. As they feed, honeybees spread pollen from flower to flower. Without this process, a plant can't produce seeds or fruits. Now, a group of scientists and beekeepers have teamed up to try to figure out what's causing the alarming collapse of so many colonies. By sharing their expertise (专家的意见) in honeybee behavior, health, and nutrition, team members hope to find out what's contributing to the decline and to prevent bee disappearances in the future. It could be that disease is causing the disappearance of the bees. To explore that possibility, Jay Evans, a researcher at the United States Department of Agriculture (USDA) Bee Research Laboratory, examines bees taken from colonies that are collapsing. "We know what s healthy bee should look like on the inside, and we can look for physical signs of disease," he says. And bees from collapsing colonies don't look very healthy. "Their stomachs are worn down, compared to the stomachs of healthy bees," Evans says. It may be that a parasite is damaging the bees' digestive organs. Their immune systems may not be working as they should. Moreover, they have high levels of bacteria inside their bodies. Another cause of colony-collapse disorder may be certain chemicals that farmers apply to kill unwanted insects on crops, says Jerry Hayes, chief bee inspector for the Florida Department of Agriculture. Some studies, he says, suggest that a certain type of insecticide affects the honeybee's nervous system (which includes the brain) and memory. "It seems like honeybees are going out and getting confused about where to go and what to do," he says. If it turns out that a disease is contributing to colony collapse, bees' genes could explain why some colonies have collapsed and others have not. In any group of bees there are many different kinds of genes. The more different genes a group has, the higher the group's genetic diversity. So far scientists haven't determined the role of genetic diversity (差异) in colony collapse, but it's a promising theory, says Evans.

单选题We lived for years in a perpetual state of fear.

单选题That is a sign of its {{U}}immense{{/U}} potential. A.natural B.fatal C.tiny D.enormous

单选题Wisdom in old age depends on a fresh supply of new brain cells, a study in mice suggests.. When mature mice learn a new task, their newly generated brain cells are three times more active than their old ones, the researchers found. The findings add to a growing body of evidence that the adult brain needs a steady addition of new cells to maintain its mental faculties. Researchers found that mature mice's brain cells are much more active than before whenA. they are transplanted with new brain cells.B. they learn to do something new.C. they gain weight in the body.D. they get new cells from other mic

单选题The cheetah is {{U}}considered {{/U}}the fastest of all land animals.

单选题It can be concluded that science education has reached a new phase of development.

单选题Gunpowder was used extensively in firearms {{U}}prior to{{/U}} 1990.

单选题Nobody can {{U}}put up with{{/U}} his bad temper.

单选题She was one of the leading writers of her day. A. expected B. natural C. most important D. least

单选题Since ancient times people have found various ways to Upreserve/U meat.

单选题 下面有3篇短文，每篇短文后有5道题。请根据短文内容，为每题确定1个最佳选项。{{B}}第一篇{{/B}} Prolonging Human Life Prolonging human life has increased the size of the human population. Many people alive today would have died of childhood diseases if they had been born 100 years ago. Because more people live longer, there are more people around at any given time. In fact, it is a decrease in death rates, not an increase in birthrates that has led to the population explosion. Prolonging human life has also increased the dependency load. In all societies, people who are disabled or too young or too old to work are dependent on the rest of society to provide for them. In hunting and gathering cultures, old people who failed to follow the others were left behind to die. In times of famine, infants might be allowed to die because they couldn't survive if their parents starved, whereas if the parents survived they could have another children, in contemporary societies, people feel a moral obligation to keep people alive whether they can work or not. We have a great many people today who live past the age at which they want to work or are able to work; we also have rules that require people to retire at a certain age. Unless these people were able to save money for their retirement, somebody else must support them. In the United States many retired people live on social security cheeks that are so little that they must live in near poverty. Older people have more illness than young or middle-aged people; unless they have wealth or private or government insurance, they must often "go on welfare" if they have a serious illness. When older people become senile or too weak and ill to care for themselves, they create grave problems for their families. In the past and in some traditional cultures, they would be cared for at home until they died. Today, with most members of a household working or in school, there is often no one at home who can care for a sick or weak person. To meet this need, a great many nursing homes and convalescent hospitals (康复医院)have been built. These are often profit-making organizations, although some are sponsored by religious and other nonprofit groups. While a few of these institutions are good, most of them are simply "dumping grounds" for the dying in which "care" is given by poorly paid, overworked, and under skilled personnel.

单选题Even in a highly modernized country, manual work is still needed.A. expressiveB. physicalC. exaggeratedD. dubious

单选题Our new house is on the first floor.

单选题Compared with large aircraft, small airplanes are not as streamlined and {{U}}hence{{/U}} are less efficient.