单选题None of us understood what the lecturer was______ at.

单选题Before high school teacher Kimberly Rugh got down to business at the start of a recent school week, she joked with her students about how she'd had to clean cake out of the corners of her house after her 2-year-old son's birthday party. This friendly combination of chitchat took place not in front of a blackboard but in an, E-mail message that Rugh sent to the 145 students she's teaching at the Florida Virtual School, one of the nation's leading online high schools. The school's motto is "any time, any place, any path, any pace." Florida's E-school attracts many students who need flexible scheduling, from young tennis stars and young musicians to brothers Tobias and Tyler Heeb, who take turns working on the computer while helping out. with their family's clam-farming business on Pine Island, off Florida's southwest coast. Home-schoolers also are well represented. Most students live in Florida, but 55 hail from West Virginia, where a severe teacher shortage makes it hard for many students to take advanced classes. Seven kids from Texas and four from Shanghai round out the student body. The great majority of Florida Virtual Schoolers—80 percent—are enrolled in regular Florida public or private high schools. Some are busy overachievers. Others are retaking classes they barely passed the first time. The school's biggest challenge is making sure that students aren't left to sink or swim on their own. After the school experienced a disappointing course completion rate of just 50 percent in its early years,Executive Director Julie Young made a priority out of what she calls "relationship-building," asking teachers to stay in frequent E-mail and phone contact with their students. That personal touch has helped. The completion rate is now 80 percent. Critics of online classes say that while they may have a limited place, they are a poor substitute for the face-to-face contact and socialization that take place in brick-and-mortar classrooms. Despite opportunities for online chats, some virtual students say they'd prefer to have more interaction with their peers. Students and parents are quick to acknowledge that virtual schooling isn't for everyone. "If your child's not focused and motivated, I can only imagine it would be a nightmare," says Patricia Haygood of Orlando, whose two daughters are thriving at the Florida school. For those who have what it takes, however, virtual learning fills an important niche. "I can work at my own pace, on my own time," says Hackney. "It's the ultimate in student responsibility./

单选题 The climate of Earth is changing. Climatologists are confident that over the past century, the global average surface temperature has increased by about half a degree Celsius. This warming is thought to be at least partly the result of human activities, such as the burning of fossil fuels and the clearing of forests for agriculture. As the global population grows and national economies expand, the global average temperature is expected to continue increasing by an additional 1.0~C to 3.5℃by the year 2100. Climate change is one of the most important environmental issues facing humankind. Understanding the potential impacts of climate change for natural ecosystems is essential if we are going to manage our environment to minimize the negative consequences of climate change and maximize the opportunities that it may offer. Because natural ecosystems are complex, nonlinear systems, it follows that their responses to climate change are likely to be complex. Climate change may affect natural ecosystems in a variety of ways. In the short term, climate change can alter the mix of plant species in land ecosystems such as grasslands. In the long term, climate change has the potential to dramatically alter the geographic distribution of major vegetation types—savannas, forests, and climate change can also potentially alter global ecosystem processes, including the cycling of carbon, nitrogen, phosphorus, and sulfur. Moreover, changes in these ecosystem processes can affect and be affected by changes in the plant species of the ecosystem and vegetation type. All of the climate change—induced alterations of natural ecosystems affect the services that these ecosystems provide to humans. The global average surface temperature increase of half a degree .Celsius observed over the past century has been in part due to differential changes in daily maximum and minimum temperatures, resulting in a narrowing of the diurnal temperature range. Decreases in the diurnal temperature range were first identified in the United States, where large-area trends showed that maximum temperatures have remained constant or increased only slightly, whereas minimum temperatures have increased at a faster rate. In this issue, Alward etal. report on the different sensitivities of rangeland plants to minimum temperatures increases.

单选题Under the deteriorating social condition, a new stable order is demanded to ______ the social foundation against its collapse. A. cripple B. buttress C. abandon D. suspend

单选题The market is a concept. If you are growing tomatoes in your backyard for sale, you are producing for the market. You might sell some to your neighbour and some to the manager of the local supermarket. But in either case, you are producing for the market. Your efforts are being directed by the market. If people stop buying tomatoes, you will stop producing them. If you take care of a sick person to earn money, you are producing for the market. If your father is a steelworker or a truck driver or a doctor or a grocer, he is producing goods or service for the market. When you spend your income, you are buying things from the market. You may spend money in stores, supermarkets, gas stations, and restaurants. Still you are buying from the market. When the local grocer hires you to drive the delivery truck, he is buying your labour in the labour market. The market may seem to be something abstract. But for each person or business who is making and selling. It's very real. If nobody buys your tomatoes, it won't be long before you get the message. The market is telling you something. It's telling you that you are using energies and resources in doing something the market doesn't want you to do.

单选题The possibility that a virus causes human cancer is indicated by ______. A. the fact that viruses have been known to mutate B. the fact that a cancer-immune individual may lose his immunity C. the fact that production of human cancer cells might be due to a genetic factor D. the fact that man is host to many viruses

单选题The author obviously believes that, in the incident, FDA failed to______

单选题English people often take umbrellas with them when they go out because they don't want to be______in a rain. A. seized B. got C. captured D. caught

单选题All ______ is a steady supply of water to the farmland. A. which needs B. that is needed C. the thing is needed D. need

单选题Passage Five There are many commonly held beliefs about eyeglasses and eyesight that are not proven facts. For instance, some people believe that wearing glasses too soon weakens the eyes. But there is no evidence to show that the structure of eyes is changed by wearing glasses at a young age. Wearing the wrong glasses, however, can prove harmful. Studies show that for adults there is no danger, but children can develop loss of vision if they have the wrong glasses. We have all heard some of the common myths about how eyesight gets bad. Most people believe that reading in dim light causes pool eyesight, but that is unique. Too little light makes the eyes work harder, so they do get tired and strained. Eyestrain also results from reading a lot, reading in bed, and watching too much television. But, although eyestrain may cause some pain or headaches, it does not permanently damage eyesight. Another myth about eyes is that they can be replaced, or transferred from one person to another. There are close to one million nerve fibers that connect the eyeball to the blain, and as if yet it is impossible to attach them all in a new person. Only certain parts of the eye--the cornea and the retina-- can be replaced. But if We keep clearing up the myths and learning more about the eyes, someday a full transplant may be possible!

单选题The leader of the expedition ______ everyone to follow his example. [A] promoted [B] reinforced [C] sparked [D] inspired

单选题D. pledge

单选题Which of the following is NOT included in G. Leech's seven types of meaning? A. Connotative meaning. B. Denotative meaning. C. Conceptual meaning.

单选题The swine flu will probably return in force earlier than seasonal flu usually begins, federal health officials predicted Friday, saying they expected it to erupt as soon as schools open rather than in October or November. The swine flu is still circulating in the United States, especially in summer camps, even though hot weather has arrived and the regular flu season ended months ago, "so we expect challenges when people return to school, when kids are congregating together," Dr. Anne Schuchat, director of respiratory diseases at the Centers for Disease Control and Prevention, said in a telephone news conference held jointly with vaccine experts from the Food and Drug Administration and the Department of Health and Human Services. It is still unclear how many doses of a swine flu vaccine will be available by then, and officials have been reluctant to make firm predictions beyond saying that they expect tens of millions, rather than hundreds of millions, and they plan to distribute them to people who are the most vulnerable, like pregnant women and people who are the most likely to encounter the flu, like health care workers. The number of doses available will depend on how fast seed strains grow, how much protection a small dose provides, and whether immune-system boosters called adjuvants are needed and prove to be safe; adjuvants are not used in American flu vaccines now. Clinical trials testing those questions are expected to take another couple of months, said Dr. Jesse L. Goodman, director of the F. D．A．'s Center for Biologics Evaluation and Research. Assuming a swine flu vaccination campaign begins, it will be voluntary, Dr. Schuchat emphasized, but she "strongly encouraged" pregnant women to get both a seasonal flu shot and a swine flu shot when they are available. The C．D．C．has been closely following the disease in the Southern Hemisphere winter, and it is mimicking the patterns seen in the United States and Mexico in the spring, she said. Most infections and most serious cases are in children and young adults, and those with underlying conditions, including pregnancy, are the most likely to die. Dr. Schuchat likened the spread's unpredictability to that of popcorn: one city could see an explosion of cases and overwhelmed hospitals while another saw few. Her most important message, she added, was that "the virus isn't gone, and we fully expect there will be challenges in the fall. /

单选题______belongs to "stream of consciousness" school.

单选题{{B}}Passage One{{/B}} The concept of personal choice in relation to health behaviors is an important one. An estimated 90 percent of all illnesses may be preventable if individuals would make sound personal health choice based upon current medical knowledge. We all enjoy our freedom of choice and do not like to see it restricted when it is within the legal and moral boundaries of society. The structure of American society allows us to make almost all our own personal decisions that may concern our health. If we so desire, we can smoke, drink excessively, refuse to wear seat belts, eat whatever foods we want, and live a completely sedentary life-style without any exercise. The freedom to make much personal decision is a fundamental aspect of our society, although the wisdom of these decisions can be questioned. Personal choices relative to health often cause a difficulty. As one example, a teenager may know the facts relative to smoking cigarettes and health but may be pressured by friends into believing it is the socially accepted thing to do. A multitude of factors, both inherited and environmental, influence the development of health-related behaviors, and it is beyond the scope of this text to discuss all these factors as they may affect any given individual. However, the decision to adopt a particular health-related behavior is usually one of personal choice. There are healthy choices and there are unhealthy choices. In discussing the morals of personal choice, Fries and Crapo drew a comparison. They suggest that to knowingly give oneself over to a behavior that has a statistical probability of shortening life is similar to attempting suicide. Thus, for those individuals who are interested in preserving both the quality and quantity of life, personal health choices should reflect those behaviors that are associated with a statistical probability of increased vitality and longevity.

单选题______ , their use is impossible in many inland places.

单选题(2007)We are wanted______.