单选题Tomcoulddosomebrilliant_______ofourEnglishteacher.

单选题The United States was trying hard {{U}}to smoke the enemy out of the holes{{/U}} in the target country.

单选题Nor has Washington yet ______ to Mexican demands for a treaty specifying extradition for U. S. officials who disregard the new stricture. A. profaned B. contemplated C. acceded D. manipulated

单选题______, water is composed of two parts hydrogen and one part oxygen.

单选题From the way she spoke you could tell she was speaking from ______.

单选题According to the author, those who wanted to work as scientists ______.

单选题At that time leukemia was almost inevitably ______, but today, more than half of the people with leukemia get a cure.

单选题One reaction to all the concern about tropical deforestation is a blank stare that asks the question, "Since I don't live in the tropics, what does it have to do with me?" The answer is that your way of life, wherever you live in the world, is tied to the tropics in many ways. If you live in a house, wash your hair, eat fruit and vegetables, drink soda, or drive a car, you can be certain that you are affected by the loss of tropical forests. Biologically, we are losing the richest regions on earth when, each minute, a piece of tropical forest the size of ten city blocks vanishes. As many as five million species of plants, animals and insects, 40 to 50 percent of all living things, live there, and are being irrevocably lost faster than they can be found and described. Their loss is incalculable. Take medicine, for example. Fewer than one percent of tropical forest plants have been examined for their chemical compounds. Nonetheless, scientists have integrated a wealth of important plants into our everyday lives. The West African calabar bean is used to treat glaucoma, while the sankerfoot plant of India yields reserpine, essential for treating hypertension. A West African vine provides the basis for strophanthus, a heart medicine. Quinine, an alkaloid derived from boiling the bark of the cinchona tree, is used to prevent and treat malaria. Derivatives from the rosy periwinkle offer a 99 percent chance of remission for victims of lymphocytie leukemia, as well as a 59 percent chance of recovery from Hodgkin' s disease. In fact, of the 3,000 plant species in the world known to contain anti-cancer properties, 2,100 ate from the tropical rain forest. Then there is rubber. For many uses, only natural rubber from trees will do, synthetics are not good enough. Today, over half of the world' s commercial rubber is produced in Malaysia and Indonesia, while the Amazon' s rubber industry produces much of the world' s four million tons. Adding ammonia to rubber produces latex which is used for surgical gloves, balloons, adhesives, and foam rubber. Latex, plus a weak mixture of acid results in sheet rubber used for footwear and many sporting goods. Literally thousands of tropical plants are valuable for their industrial uses. Many provide fiber and canes for furniture, soundproofing and insulation. Palm oil, a product of tile tropics, brings to your table margarine, cooking oil, bakery products, and candles. Palm nut oil, from the seed kernel inside the fruit, is found in soap, candles, and mayonnaise. The sap from Amazonian copaiba trees, poured straight into a fuel tank, can power a truck. At present, 20 percent of Brazil ' s diesel fuel comes from this tree. An expanded use of this might reduce our dependency on irreplaceable fossil fuels. Many scientists assert that deforestation contributes to the greenhouse effect, the heating of the earth from increased carbon dioxide in the atmosphere. As we destroy forests, we lose their ability to convert carbon dioxide into oxygen. Carbon dioxide levels could double within the next half-century, warming the earth by as much as 4.5 degrees. The result.'? A partial melt-down of the polar ice caps, raising sea levels as much as 24 feet. A rise of 15 feet would threaten anyone living within 35 miles of the coast. Far-fetched? Perhaps, but scientists warn that by the time we realize the severe effects of tropical deforestation, it will be 20 years too late. Can tropical deforestation affect our everyday lives? We only have to look at the catalogued tropical forests and the abundance of wondrous products from which we benefit every day to know the answer. After all, the next discovery could be a cure for cancer or the common cold, or the answer to feeding the hungry, or fuelling our world for centuries to come. Comprehension Questions

单选题When the news of his ______ with the enemy became known, he was hanged in effigy.

单选题 At the Kyoto conference on global warming in December 1997, it became abundantly clear how complex it has become to work out international agreements relating to the environment because of economic concerns unique to each country. It is no longer{{U}} (21) {{/U}}to try to forbid certain activities or to reduce{{U}} (22) {{/U}}of certain substances. The global challenges of the inter-link between the environment and development increasingly{{U}} (23) {{/U}}us to the core of the economic life of states. During the late 1980s we were able, through international agreements, to make deep{{U}} (24) {{/U}}in emissions{{U}} (25) {{/U}}the ozone layer. These reductions were made possible{{U}} (26) {{/U}}the harmful substances could be replaced{{U}} (27) {{/U}}negative effects on employment and the economies of states. Although the threat of global warming has been known to world for decades, we know that the effects of measures,{{U}} (28) {{/U}}harsh measures taken in some countries, would be nullified if{{U}} (29) {{/U}}countries do not control their emissions. Important and populous low- or medium-income countries are not{{U}} (30) {{/U}}willing to undertake legal commitments about their energy uses. We must,{{U}} (31) {{/U}}find a solution to the threat of global warming early in the 21st century. Such a{{U}} (32) {{/U}}would require a degree of shared vision and common responsibilities new to humanity. Success lies in the force of imaginations, in imagining what{{U}} (33) {{/U}}if we failed to act. Although many living in cold regions would welcome the global-warming effect of a warmer summer,{{U}} (34) {{/U}}would cheer arrival of the{{U}} (35) {{/U}}tropical diseases, especially where there has been none.

单选题Thanks to sponsorship, the fee to ______ will be＄25 ______ and participants will have to pay only travel expenses.

单选题I am standing on the seventh-floor balcony of an apartment building overlooking the heart of Moscow. It is a dark city, some might say grim. It looks and feels as if it has been worn down to its bare bones: broken sidewalks, cracked facades, weeds rooted in the very mortar. This city is not easy to look at. So I avert my eyes, and they settle on a little boy sleeping inside the apartment. His name is Alexei. He is 7. With every rise and fall of his chest, Moscow, the used, broken city, is renewed for me a thousand times. A dark place has given me light in the form of my adoptive son. Alexei has been my son for only two days, but I have been waiting three years for him. That's when I began the adoption process, three years ago, before I even knew of Alexei's existence. Never in my imaginings did I think that I would one day be so far from home, counting my son's breaths, counting the hours until we would board a plane for America, a place that he had no conception of "Alexei, " I had said through a translator as I knelt before him at the orphanage and helped him with his socks. " What do you know about America?" His reply was immediate: "I will have all the gum I want. " Most people adopt infants or very little children so that as much of their history as possible will be given to them by their parents. But Alexei carries a radiance of native culture: his memories of orphanage life in the once-closed city of Tula; the large, gracious, doting Russian women who have cared for him all his life; the aromatic Russian food he loves, and the language, that impossible, expressive, explosive Russian language that sometimes separates me from him like a wall, but also summons us to heroic legends as we attempt to communicate. I have been in Russia for two weeks. But it wasn't until the fourth day that I was brought to see Alexei. My Russian contact drove me through 100 miles of a country struggling to get back on its feet after years of internal neglect; pitted roadways, crumbling bridges, warped roofs. It made me recall what someone had once said about Russia, that she is a third-world country with a first-world army. We finally came to an orphanage. Once inside, I stood in a near-empty room, reminding myself that this was the culmination of three years of scrutiny, disappointment, and dead-ends. There were moments when I had told myself, "It's so much easier to have a kid the natural way. Nobody asks any questions. " But as a single man, a biological child was not a ready option. I now recognized these as idle thoughts, for I realized that Alexei, even sight unseen, would be as much mine as if he were my natural son. The door opened. A woman came out, her hand on the shoulder of a little boy just awakened from sound sleep. I gave Alexei a Pez candy dispenser, something as alien to him as life in America. After a few moments of scrutiny, he filled with candy, a sure sign of intelligence, for Pez, dispensers are notoriously difficult to load. At the end of our first meeting I knelt before Alexei and told him I would be back to get him in a week.

单选题A person's caloric requirements vary ______ his life.

单选题The WHO has to come up with new and effective measures to______the spread of the epidemic disease.

单选题Between the invention of agriculture and the commercial revolution that marked the end of the Middle Ages, wealth and technology developed slowly indeed. Medieval historians tell of the centuries it took for key inventions like the watermill or the heavy plow to diffuse across the landscape. During this period, increases in technology led to increases in the population, with little if any appearing as an improvement in the median standard of living. Even the first century of the industrial revolution produced more "improvements" than "revolutions" in standards of living. With the railroad and the spinning and weaving of textiles as important exceptions, most innovations of that period were innovations in how goods were produced and transported, and in new kinds of capital, but not in consumer goods. Standards of living improved but styles of life remained much the same. The eighteenth and nineteenth centuries saw a faster and different kind of change. For the first time, technological capability outran population growth and natural resource scarcity. By the last quarter of the nineteenth century, the typical inhabitant of the leading economies—a British, a Belgian, an American, or an Australian had perhaps three times the standard of living of someone in a pre-industrial economy. Still, so slow was the pace of change that people, or at least aristocratic intellectuals, could think of their predecessors of some two thousand years before as effectively their contemporaries. Marcus Tullius Cicero, a Roman aristocrat and politician, might have felt more or less at home in the company of Thomas Jefferson. The plows were better in Jefferson's time. Sailing ships were much improved. However, these might have been insufficient to create a sense of a qualitative change in the order of life for the elite. Moreover, being a slave of Jefferson was probably a lot like being a slave of Cicero. So slow was the pace of change that intellectuals in the early nineteenth century debated whether the industrial revolution was worthwhile, whether it was an improvement or a degeneration in the standard of living. Opinions were genuinely divided, with as optimistic a liberal as John Stuart Mill coming down on the "pessimist" side as late as the end of the 1840s. In the twentieth century, however, standards of living exploded. In the twentieth century, the magnitude of the growth in material wealth has been so great as to make it nearly impossible to measure. Consider a sample of consumer goods available through Montgomery Ward in 1895 when a one-speed bicycle cost $65. Since then, the price of a bicycle measured in "nominal" dollars has more than doubled (as a result of inflation). Today, the bicycle is much less expensive in terms of the measure that truly counts, its "real" price: the work and sweat needed to earn its east. In 1895, it took perhaps 260 hours' worth of the average American worker's production to amass enough money to buy a one-speed bicycle. Today an average American worker can buy one—and of higher quality—for less than 8 hours worth of production. On the bicycle standard (measuring wealth by counting up how many bicycles the labor can buy) the average American worker today is 36 times richer than his or her counterpart was in 1895. Other commodities would tell a different story. An office chair has become 12.5 times cheaper in terms of the time it takes the average worker to produce enough to pay for it. A Steinway piano or an accordion is only twice as cheap. A silver teaspoon is 25 percent more expensive. Thus the answer to the question "How much wealthier are we today than our counterparts of a century ago?" depends on which commodities you view as important. For many personal services—having a butler to answer the door and polish your silver spoons—you would find little difference in average wealth between 1895 and 1990: an hour of a butler's time costs about the same then as now. For mass-produced manufactured goods—like bicycles—we are wealthier by as much as 36 times.

单选题According to the passage, the risk of infection from airborne microorganisms would likely be greater during a ______.

单选题It is rather______that we still do not know how many species there are in the world today.