单选题Not until the advent of histochemistry could the anatomist see through the microscope which cells carry specific enzymes or gauge how active these enzymes are in different cells under various conditions. A. discern B. grasp C. measure D. estimate

单选题Tom qualified ______ an engineer before attending a business school. A. like B. as C. with D. to

单选题You used to go swimming in the lake before it became polluted, ______?

单选题The agriculture revolution in the nineteenth century involved two things: the invention of labor-saving machinery and the development of scientific agriculture. Labor-saving machinery naturally appeared first where labor was scarce. "In Europe," said Thomas Jefferson, "the object is to make the most of their land, labor being sufficient; here it is to make the most of our labor, land being abundant." It was in America, therefore, that the great advances in the nineteenth century agricultural machinery first came. At the opening of the century, with the exception of a crude(粗糙的) plow, farmers could have carried practically all of the existing agricultural tools on their backs. By 1860, most of the machinery in use today had been designed in an early form. The most important of the early inventions was the iron plow. As early as 1890 Charles Newbolt of New Jersey had been working on the idea of a cast-iron plow and spent his entire fortune in introducing his invention. The farmers, however, would home none of it, claiming that the iron poisoned the soil and made the weeds grow. Nevertheless, many people devoted their attention to the plow, until in 1869, James Oliver of South Bend, Indiana, turned out the first chilled-steel plow.

单选题It could be inferred from the last paragraph that______

单选题At the time when this article was written, the situation for doctors in Philadelphia seemed to be

单选题To ______ the world peace has been one of the most crucial functions of the United Nations since it was founded in 1945.

单选题______ country in the world should do her best to keep the world peace.

单选题 Evidence is widespread that HIV-infected persons slow to ______ their unsafe behavior.

单选题A variety of significant, attractive short-term benefits will drive the development of modern self-sufficient homes. These include security from severe weather, climate changes, and natural disasters; security from infectious diseases and related health problems; a fresh and nutritious diet; a dependable food supply; and security from global unrest. But the real benefit of Earth Homes will be the long-term sustainability of our planet. It should be no secret that the planet is experiencing unusual weather and climate abnormalities. The 10 hottest years in recorded history have all been in the last 15 years; the 1990s were the hottest decade on record. The Midwestern heat wave of 1995 killed 669 people in Chicago. In 1996, we had a season of record heat spells, and 1997 was the single wan nest year on record--until 1998 shattered global temperature records. Record-high temperatures throughout the southern United States during the summer of 1998 forced the shutdown of Walt Disney World's water parks because of the threat of a viral encephalitis outbreak. The United Nations and insurers blame unusual weather for thousands of deaths and billions of dollars in damage. Many scientists agree that the emissions resulting from human activities are substantially increasing the atmospheric concentration of the greenhouse gases. These increases will enhance the greenhouse effect, resulting in warming of the earth's surface. In 1990, scientists predicted that, if greenhouse gas emissions are not sharply decreased, we might experience a 1C to 3C rise in global temperatures. They suggested that we would have to cut in half our use of coal, oil, and gas in order to lower our emissions enough to maintain concentrations of greenhouse gases at the current levels. Proof of warning includes a decrease in the amount of snow that covers the Northern Hemisphere, a simultaneous decrease in Arctic sea ice, continued melting of alpine glaciers, and a rise in sea level. Rain has even been reported for the first time in Antarctica, and an ice-free patch of ocean about a mile wide has recently opened near the North Pole. Meanwhile, studies have shown that the carbon dioxide concentration in our atmosphere has been steadily increasing since 1958. Even though the rate of emissions from fossil fuels has been reduced, concentration has risen consistently. In 1995, the size of the ozone hole over Antarctica doubled to about the size of Europe. For the first time in recorded history, the hole stretched over populated areas, exposing residents in southern Chile and Argentina to very high levels of ultraviolet (UV) radiation. Studies have shown that a 1% decrease in ozone in the stratosphere produces a 2% increase in UV radiation reaching the ground, posing more risks to humans.

单选题But, in our enthusiasm to discover our heritage, we are ruining the very scenery we go to enjoy, damaging natural habitats, ______ down footpaths, disturbing wildlife, polluting the air and dropping litter.

单选题下面的短文后列出了10个句子，请根据短文的内容对每个句子作出判断：如果该句提供的是正确信息，选择A；如果该句提供的是错误信息，选择B；如果该句的信息文中没有提及，选择C。在答题卡相应位置上将答案选项涂黑。Setting Effective Goals　　Avital Schweitzer, 17, is clearly goal directed.She works hard to achieve

单选题The author's attitude toward Richard Lamm's remark is one of ______.

单选题Cancer is the world's top 'economic killer' as well as its likely leading cause of death. Cancer costs more in 26 and lost life than AIDS, malaria, the flu and other diseases that spread person-to-person. Chronic diseases including cancer, heart disease and diabetes 27 for more than 60 percent of deaths worldwide but less than 3 percent of public and private 28 for global health, said Rachel Nugent of the Center for Global Development, a Washington-based policy research group. Money shouldn't be taken away from fighting diseases that 29 person-to-person, but the amount 30 to cancer is way out of whack (重击) with the impact it has, said Otis Brawley, the cancer society's chief medical officer. Cancer's economic toll (损耗) was $895 billion in 2008—equivalent to 1.5 percent of the world's gross 31 product, the report says. That's in terms of disability and years of life lost—not the cost of treating the disease, which wasn't addressed in the report. Many groups have been pushing for more attention to non-infectious causes of death, and the United Nations General Assembly has set a meeting on this a year from now. Some policy experts are 32 it to the global initiative that led to big increases in spending on AIDS nearly a decade ago. 'This needs to he discussed at the UN—how we are going to deal with this rising burden of 33 disease', said Dr. Andreas Ullrich, medical officer for cancer control at WHO. Researchers used the World Health Organization's death and disability reports, and economic data from the World Bank. They 34 disability-adjusted life years, which reflect the impact a disease has on how long and how 35 people live. A. productively B. supplying C. shifting D. spread E. account F. funding G. calculated H. devoted I. productivity J. chronic K. comparing L. domestic M. doubtful N. clumsily O. disability

单选题From the stories which exemplify Roosevelt' s affection for his family members, we can infer that ______.

单选题People who disagree with women's opinions believe ______.

单选题June came and the hay （干草） was almost ready for cutting. On Midsummers Eve, which was a Saturday, Mr. Jones went into Willington and got so drunk at the Red Lion that he did not come back until m

单选题 Coronary heart attacks occur more commonly in those with high blood pressure, in the obese, in the cigarette smokers, and in those ______ to prolonged emotional and mental strain.