An early invention by Albert Einstein has been rebuilt by scientists at Oxford University. They are trying to develop an environmentally friendly refrigerator that runs without electricity. We all know that modern fridges cause damage to the environment. They work by using a kind of man-made greenhouse gas called Freon , which is far more damaging than carbon dioxide. Now Malcolm McCulloch, an electrical engineer at Oxford, is leading a three-year project to develop appliances that can be used in places without electricity. His team has completed a prototype of a fridge patented in 1930 by Einstein. It used only pressurized gases to keep things cold. The design was partly used in the first refrigerators, but the technology was dropped when more efficient compressors became popular in the 1950s. That meant a switch to using Freon. Einstein's idea uses butane and water and takes advantage of the fact that liquids boil at lower temperatures, when the air pressure around them is lower. "If you go to the top of Mount Qomolangma, water boils at a much lower temperature than it does when you're at sea level and that's because the pressure is much lower up there," said McCulloch.At one side is the evaporator , a bottle that contains liquid butane. "If you introduce a new vapor above the butane, the liquid boiling temperature decreases and, as it boils off, it takes energy from the surroundings to do so," says McCulloch. "That's what makes it cold." The gas fridges based on Einstein's design were replaced by Freon-compressor fridges partly because Einstein's design was not very efficient. But McCulloch thinks that by changing the design and replacing the types of gases used it will be possible to quadruple the efficiency. However, McCulloch's fridge is still in its early stages. "It's very much a prototype," he said. "Give us another month and we'll have it working." We can learn from the text that the prototype completed _ . A) changed the air pressure around it B) was tested on the top of Mount Everest C) increased the liquid boiling temperature D) used only pressurized gases to keep things cold
D
(Question)
Treatment for HIV has become more widespread, especially in poorer countries. It's also become cheaper, as medicine companies have lowered their prices for life-saving anti-retroviral drugs . But these drugs are still expensive and many countries are looking to create the biggest impact with limited resources. That's where World Health Organization guidelines come in, says Rochelle Walensky, a disease researcher from Harvard. Walensky and her colleagues used computer programs to model the most cost-effective disease interventions , as well as collected data from clinics in Africa and India about what works best. They found that among the choices of what to do first, earlier anti-retroviral therapy improved five-year survival dramatically and resulted in the longer life expectancy. But cost-effective doesn't always mean affordable, especially for governments in poor countries. Countries still have to make difficult choices about how much treatment they can afford. People in Nairobi, Kenya on Thursday, Dec. 9, 2010, protest a potential free trade area agreement between the EU and India that could see cheap anti-AIDS drugs phased out . However, Walensky notes that first-line anti-retrovirals--those medicine given to newly diagnosed patients that can keep away from symptoms for years - are much cheaper than they were a decade ago. "Second-line therapy have come down quite a bit but not to the level of first-line and countries are having a hard time affording them and increasingly over time, people are going to fail first-line therapy and they're going second-line therapy and then, eventually, they're going to need third-line therapy, some of them." According to Walensky, history has shown that drug prices can come down when international pressure is applied to drug makers. But for now, she says, countries should focus on treating as many people as they can, as early as possible Her paper is published in the online journal PLoS Medicine. The passage serves as a(n) _ to Rochelle Walensky 's study. A) assessment B) comment C) introduction D) background
(Answer)
C
Ques: About 500 years ago, the Spanish explorer Christopher Columbus proved the Earth was round. Now American author Thomas Friedman tells us the Earth is flat in his best seller: The World Is Flat: A Brief History of the Twenty-First Century. If he is not joking, then why is the world flat? Friedman says it is due to technological forces. Because of the Internet and the World Wide Web, he believes geographical barriers are disappearing. Individuals and companies around the world can cooperate or compete on the same level. Bill Gates explains the meaning of this transformation best. "Thirty years ago," he tells Friedman, "if you had to choose between being born a genius in Shanghai and an average person in Poughkeepsid (a city in southeast New York), you would have chosen Poughkeepsie because your chances of living a wonderful life were much greater there. "Now," Gates says, "I would rather be a genius born in China than an average person born in Poughkeepsie." This shows that success today is determined more by ability than by location. "Globalization 3.0", as he calls it, is driven by ambitious individuals: freelancers and creative new businesses all over the world, especially in India and China. They can compete not just for low-salary manufacturing industry but, increasingly, for the highest-end research and design work as well. Big companies have played another important role in this globalization process. They move their factories from one country to another to cut costs. It's usual now for an engineer in China to be working for an American company. The Internet keeps them in constant touch with their American partners. People everywhere, from the US to China, have procedures of the same standard for getting their work done. The Reuters news agency provides a good example. The company moved its operation offices from London and New York to India. The Indian employees have the necessary technical skills. But the salaries and office rents are less than one-fifth of what they would be in New York or London. Friedman tells us that the Earth is flat _ . A) to prove Columbus's idea is wrong B) based on the wide use of the Internet C) using some technological forces D) because of the great change of the Earth itself
Ans: B
Millions of years ago dinosaurs lived on the earth. In the days of dinosaurs the whole earth was warm and wet. There were green forests and they could find enough to eat. Later, parts of the earth became cold and dry. and the forests there died. Then dinosaurs could not find enough to cat. This must be one reason why dinosaurs died out. We can guess another reason. New kinds of animals came on the earth. Some had big brains and were fast and strong. They could kill dinosaurs. There may be other reasons that we don't know about yet. Scientists are trying to make more discoveries about dinosaurs. Dinosaurs were of many sizes and shapes . Some were as small as chickens, while some were about 90 feet long. There were also terrible fights between dinosaurs. They might have happened more than 100 million years ago. Though there was no man to see any of the fights, we can be told by the animal's footprints that fight did take place. According to the passage, dinosaurs did exist only _ on the earth. A) for millions of years B) millions of years ago C) more than 100 millions years ago D) when it was warm and wet somewhere
B