单选题The foreign minister would reveal nothing about his recent tour of the Middle East {{U}}beyond{{/U}} what had already been announced at the press conference.

单选题According to the passage, alcohol has something to do with bad breath mainly because ______.

单选题I didn"t need any specific medical input or ______ control, although I was in a mess physically and I did need to rest, relax, and recharge myself.

单选题He leaned out of an upstairs window and felt a current of warm air______from the street.(2013年3月中国科学院考博试题)

单选题Climatic conditions are delicately adjusted to the composition of the Earth's atmosphere. If there were a change in the atmosphere--for example, in the relative proportions of atmosphere gases--the climate would probably change also. A slight increase in water vapor, for instance, would increase the hem-retaining capacity of the atmosphere and would lead to a rise in global temperatures. In contrast, a large increase in water vapor would increase the thickness and extent of the cloud layer, reducing the mount of solar energy reaching the Earth' surface. The level of carbon dioxide, CO2 in the atmosphere has important effect on climatic change. Most of the Earth's incoming energy is short-wavelength radiation, which tends to pass through atmospheric CO2 easily. The Earth, however, reradiates much of the received energy as a long-wavelength radiation, Which CO2 absorbs and then remits toward the Earth. This phenomenon, known as the greenhouse effect, can result in an increase in the surface temperature of a planet. An extreme example of the effect is shown by the Venus, a planet covered by heavy clouds composed mostly of CO2, whose surface temperatures have been measured at 430℃. If the CO2 content of the atmosphere is reduced, the temperature falls. According to one respectable theory, if the atmospheric CO2 concentration were halved, the Earth would become completely covered with ice. Another equally respectable theory, however, states that a halving of the CO2 concentration would lead only to a reduction in global temperatures of 3℃. If, because of an increase in forest fires or volcanic activity, the CO2 content of the atmosphere increased, a warmer climate would be produced. Plant growth, which relies on both the warmth and the availability of CO2, would probably increase. As a consequence, plants would use more and more CO2. Eventually CO2 levels would diminish and the climate, in turn, would become cooler. With reduced temperatures many plants would die; CO2 would thereby be returned to the atmosphere and gradually the temperatures would rise again. Thus, if this process occurred, there might be a long-term oscillation in the amount of CO2 present in the atmosphere, with regular temperature increase and decrease of a set magnitude. Some climatologists argue that the burning of fossil fuels has raised the level of CO2 in the atmosphere and has caused a global temperature rise of at least 1℃. But a supposed global temperature rise of 1℃ may in reality be only several regional temperature increase, restricted to areas where there are many meteorological stations and caused simply by shifts in the pattern of atmospheric circulation. Other areas, for example the Southern Hemisphere oceanic zone, may be experiencing an equivalent temperature decrease that is unrecognized because of the shortage of meteorological recording stations.

单选题It is said that science has become too complex to acknowledge the existence of uni versal truths. A. address B. declare C. affirm D. Perceive

单选题The Uplainer/U a bowerbird's plumage, the more brightly it decorates its nest to attract a mate.

单选题To which one of the following questions does the author provide enough information to formulate an answer?

单选题The each revolves both round the sun and on its own axis.

单选题Smoking makes one six times more likely to get oral cancer partly because the smoke constantly assaults the tissues that line the mouth and throat.

单选题Henry Tanner received widespread recognition for his naturalistic paintings of plantation life. A. profits B. storage C. attention D. invitations

单选题The terms wad and frog refer to two different animals belonging to different genuses, and careful students ______ the two.

单选题Questions 27—30 are based on a report about generation gap. You now have 20 seconds to read Questions 27—30.

单选题In my opinion Elizabeth and Henry are not ______ friends as lovers.

单选题What is the author's attitude towards doctors?

单选题It's all annual back-to-school routine. One morning you wave goodbye, and that (56) evening you're burning the late-night oil in sympathy. In the race to improve educational standards, (57) are throwing the books at kids. (58) elementary school students are complaining of homework (59) . What's a well-meaning parent to do? As hard as (60) may be, sit back and chill, experts advise. Though you've got to get them to do it, (61) helping too much, or even examining (62) too carefully, you may keep them (63) doing it by themselves. "I wouldn't advise a parent to check every (64) assignment," says psychologist John Rosemond, author of Ending the Tough Homework. "There's a (65) of appreciation for trial and error. Let your children (66) the grade they deserve. " Many experts believe parents should gently look over the work of younger children and ask them to rethink their (67) . But "you don't want them to feel it has to be (68) ," she says. That's not to say parents should (69) homework first, they should monitor how much homework their kids (70) . Thirty minutes a day in the early elementary years and an hour in (71) four, five, and six is standard, says Rosemond. For junior-high students it should be " (72) more than an hour and a half," and two for high school students. If your child (73) has more homework than this, you may want to check (74) other parents and then talk to the teacher about (75) assignments.

单选题The police stopped me the other day as I was driving home, because I was ______ the speed limit.

单选题Historically, the spread, prevalence, and very existence of contagious disease have wholly depended on the growth and concentration of human populations.【R1】______And though the last century has witnessed substantial worldwide success in combating many past scourges—such as polio and smallpox—infectious diseases still claim more lives than any other group of diseases. The prevailing demographic trends continue to create a crowded human " medium" that both invites and is vulnerable to infection. The share of humanity living in cities with more than 1 million people has surged from less than 5 percent in 1900 to nearly 40 percent today, creating the ideal setting for the resurgence of old infectious diseases as well as the development of new ones.【R2】______ Overcrowding—the increased proximity of susceptible individuals—is a principal risk factor for the incidence and spread of all major infectious diseases, including tuberculosis, dengue fever, malaria, and acute respiratory illnesses, which are unable to spread and survive in low population densities.【R3】______ Aside from sheer growth and increasing density, the urbanization under way in developing nations is often accompanied by deteriorating health indicators and increased exposure to disease risk factors. Access to clean water, good hygiene, and adequate housing are sorely lacking in developing nations. As a result, waterborne infections such as cholera and other diarrheal diseases account for 90 percent of all infectious diseases in developing countries—and 40 percent of all deaths in some nations.【R4】______ In both industrial and developing nations, incidences of a wide range of infectious diseases, including tuberculosis, diarrheal diseases, and HIV/AIDS, are considerably higher in urban slums— where poverty and compromised health define the way of life—than in the rest of the city.【R5】______A. Key disease carriers, such as insects and rats, thrive in crowded urban settings, further facilitating spread.B. The unprecedented population densities in fourteenth-century Europe, for example, led to the plague outbreak that claimed the lives of one fourth of the population.C. Although these infections are easily preventable if adequate water and sanitation are available, the vast majority of the world's population is lifelong victims.D. While new global markets have created unprecedented economic opportunities and growth, the health risks of our increasingly interconnected and fast-paced world continue to grow.E. Pathogens can more readily establish in large populations, since all infectious diseases require a critical number of vulnerable individuals in order to take root and spread.F. These areas can serve as a perpetual reservoir of disease or disease vectors, placing other parts of the city at risk of an outbreak and allowing the disease to continue evolving, often into a deadlier strain.

单选题3 Certainly no creature in the sea is odder than the common sea cucumber. All living creatures, especially human beings, have their peculiarities, but everything about the little sea cucumber seems unusual. What else can be said about a bizarre animal that" among other eccentricities, eats mud, feeds almost continuously day and night but can live with- out eating for long periods, and can be poisonous but is considered supremely edible by gourmets? For some fifty million years, despite all its eccentricities, the sea cucumber has sub- sisted on its diet of mud. It is adaptable enough to live attached to rocks by its tube feet, under rocks in shallow water, or on the surface of mud flats. Common in cool water on both Atlantic and Pacific shores, it has the ability to suck up mud or sand and digest whatever nutrients are present. Sea cucumbers come in a variety of colors, ranging from black to reddish-brown to sand-colored and nearly white. One form even has vivid purple tentacles. Usually the crea- tures are cucumber-shaped--hence their name and because they are typically rock inhabitants, this shape, combined with their flexibility, enables them to squeeze into crevices where they are safe from predators and ocean currents. Although they have voracious appetites, eating day and night, sea cucumbers have the capacity to become quiescent and live at a low metabolic rate--feeding sparingly or not at all for long periods, so that the marine organisms that provide their food have a chance to multiply. If it were not for this faculty, they would devour all the food available in a short time and would probably starve themselves out of existence. But the most spectacular thing about the sea cucumber is the way it defends itself. Its major enemies are fish and crabs. When attacked, it squirts all its internal organs into the water. It also casts off attached structures such as tentacles. The sea cucumber will eviscerate and regenerate itself if it is attacked or even touched: it will do the same if the surrounding water temperature is too high or the water becomes too polluted.

单选题It is well known that the first ______ can only work hard planting young trees for a new business, while the following people may obtain the successful fruits.