单选题What were the (consequences) of the decision she had made?

单选题Louis Sullivan, a famous American architect, varied his structures to {{U}}suit{{/U}} the local climate.

单选题{{B}}第二篇{{/B}} The use of heat pumps has been held back largely by skepticism about advertisers' claims that heat pumps can provide as many as two units of thermal energy for each unit of electrical energy used, thus apparently contradicting the principle of energy conservation. Heat pumps circulate a fluid refrigerant(致冷剂) that cycles alternatively from its liquid phase to its vapor phase in a closed loop. The refrigerant, starting as a low-temperature, lowpressure vapor, enters a compressor 'driven by an electric motor. The refrigerant leaves the compressor as a hot, dense vapor and flows through a heat exchanger called the condenser, which transfers heat from the refrigerant to a body of air. Now the refrigerant, as a high-pressure, cooled liquid confronts a flow restriction which causes the pressure to drop. As the pressure falls, the refrigerant expands and partially vaporizes, becoming chilled. It then passes through a second heat exchanger, the evaporator, which transfers heat from the air to the refrigerant, reducing the temperature o{ this second body of air. Of the two heat exchangers, one is located inside, and the other one outside the house, so each is in contact with a different body of air: room air and outside air, respectively. The flow direction of refrigerant through a heat pump is controlled by valves. When the refrigerant flow is reversed, the heat exchangers switch function. This flow-reversal capability allows heat exchangers switch function. This flow-reversal capability allows heat pumps either to heat or cool room air. Now, if under certain conditions a heat pump puts out more thermal energy than it consumes in electrical energy, has the law of energy conservation been challenged? No, not even remotely: the additional input of thermal energy into the circulating refrigerant via the evaporator accounts for the difference in the energy equation. Unfortunately, there is one real problem. The heating capacity of a heat pump decreases as the outdoor temperature falls. The drop in capacity is caused by the lessening amount of refrigerant mass moved through the compressor at one time. The heating capacity is proportional to this mass flow rate: the less the mass of refrigerant being compressed, the less the thermal load it can transfer through the heat-pump cycle. The volume {low rate of refrigerant vapor through the single-speed rotary compressor used in heat pumps is approximately constant. But cold refrigerant vapor entering a compressor is at lower pressure than warmer vapor. Therefore, the mass of cold refrigerant—and thus the thermal energy it carries—is less than ii the refrigerant vapor were warmer before compression. Here, then, lies a genuine drawback of heat pumps: in extremely cold climates—where the most heat is needed—heat pumps are least able to supply enough heat.

单选题It is seldom {{U}}acceptable{{/U}} to abbreviate words in formal writing.

单选题United States Navy Admiral Alfred Mahan wrote many books on naval strategy and sea power.

单选题Most babies can {{U}}take in{{/U}} a wide range of food easily. A. bring B. keep C. serve D. digest

单选题It"s almost 5 o"clock, time to quit .

单选题If you are Usmart/U, you'd buy now before prices go up.

单选题It"s sensible to start any exercise program gradually at first.

单选题The research team needs to Uconfer/U with the director before it begins its final report.

单选题The term "composition" refers to the way the components of a drawing are arranged by the artist.

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，为每题定1个最佳选项。{{B}}第一篇{{/B}} American Immigrants The percentage of immigrants (including those unlawfully present ) in the United states has been creeping upward for years. At 12.6 percent, it is now higher than at any point since the mid 1920s. We are not about to go back to the days when congress openly worried about inferior races polluting America's bloodstream. But once again we are wondering whether we have too many of the wrong sort newcomers. Their loudest critics argue that the new wave of immigrants cannot, and indeed do not want to, fit in as previous generations did. We now know that these racist views were wrong. In time, Italians, Romanians-and members of other so-called inferior races became exemplary Americans and contributed greatly, in ways too numerous to detail, to the building of this magnificent nation. There is no reason why these new immigrants should not have the same success. Although children of Mexican immigrants do better, in terms of educational and professional attainment, than their parents, UCLA sociologist Edward Telles has found that the gains don't continue. Indeed, the fourth generation is marginally worse off than the third. James Jackson, of the University of Michigan, has found a similar trend among black Caribbean immigrants. Telles fears that Mexican-Americans may be fated to follow in the footsteps of American blacks-that large parts of the community may become mired(陷入) in a seemingly permanent state of poverty and underachievement. Like African-Americans, Mexican-Americans are increasingly relegated to (降入)segregated substandard schools, and their dropout rate is the highest for any ethnic group in the country. We have learned much about the foolish idea of excluding people on the presumption of the ethnic/racial inferiority. But what we have not yet learned is how to make the process of Americanization work for all. I am not talking about requiring people to learn English or to adopt American ways; those things happen pretty much on their own, but as arguments about immigration hear up the campaign trail, we also ought to ask some broader question about assimilation, about how to ensure that people, once outsiders, don't forever remain marginalized within these shores. That is a much larger question than what should happen with undocumented workers, or how best to secure the border, and it is one that affects not only newcomers but groups that have been here for generations. It will have more impact on our future than where we decide to set the admissions bar for the latest ware of would-be Americans. And it would be nice if we finally got the answer right.

单选题The second part of the Internet is the" pipes" that carry data, video, e-mail messages, and text from companies such as Google, Hulu, Yahoo !, and Twitter, the millions of websites that make up Internet content and services, to customers. Some of these" pipe" providers, specifically telecom and cable companies, are already complaining that the amount of data that they have to move is rising too rapidly for them to accommodate. Video files, which are particularly large, have posed significant problems to cable companies and they have asked Washington to be able to charge more for customers who use the Internet to transfer large files. So far, the government has turned those requests down. All the following are mentioned as part of the "pipes" EXCEPTA. e-mail messages.B. video.C. text from companies.D. cable companies.

单选题The policeman wrote down all the {{U}}particulars {{/U}}of the accident

单选题Public lands can be used for energy development when

单选题Scientists Make Sweet Discovering Good news for chocoholics: the treat preferred by millions all over the world is good for you, according to American researchers at the University of California. Chocolate contains substances called flavonoids that can help maintain a healthy heart and good circulation. The researchers have discovered that cocoa acts like aspirin and that eating a bar of chocolate has also been shown to release endorphins in the body: these chemicals help to reduce pain and stress and make you feel happy. The Olmec Indians of Mexico and Central America were the first to grow cocoa beans, in about1500 BC, and the Mayas were drinking unsweetened coca hundreds of years before it became fashionable in Europe. In 1544, a delegation of Mayan nobles visited Philip of Spain and gave him jars of cocpa as a gift. Cocoa soon became fashionable in Spain and Portugal. The Spanish were the first to add sugar to their cocoa drink. By the middle of the century, solid chocolate was becoming familiar. In 1765, James Baker and John Hanan opened the first chocolate mill in the United States, introducing chocolate to the average citizen. In 1896, in Switzerland, Daniel Peter had the idea of adding milk in the chocolate-making process and produced the first milk chocolate. Since then, chocolate has grown enormously in popularity. One of the biggest chocolate-eating nations is Britain where the average man, women, and child eats nine kilos of chocolate a year. In fact, chocolate is the number one comfort food and there are more chocoholics in Britain than any where else in the world. Researchers warn that although chocolate is good for you, it should be eaten in small quantities and with no added milk.

单选题When I heard the noise in the next room, I couldn’t resist having a (peep) look.A. chance B. visit C. look D. try

单选题We have never seen such gorgeous hills.

单选题What does Moravec think of these future robots?

单选题The economy continued to exhibit signs of decline in September.