单选题She is very {{U}}conscientious{{/U}} about her work.

单选题John is eligible for this job.

单选题They strolled around the lake for an hour or so.

单选题3。He's spent years {{U}}cultivating{{/U}} a knowledge of art．

单选题Can Buildings Be Designed to Resist Terrorist Attack In the aftermath of the terrorist attack on the World Trade Center, structural engineers are trying hard to solve a question that a month ago would have been completely unthinkable: Can building be designed to withstand catastrophic blasts inflicted by terrorists? Ten days after the terrorist attacks on the twin towers, structural engineers from the University at Buffalo and the Multidisciplinary Center for Earthquake Engineering Research (MCEER) headquartered at UB traveled to ground zero as part of a project funded by the National Science Foundation. Visiting the site as part of an MCEER reconnaissance visit, they spent two days beginning the task of formulating ideas about how to design such structures and searching for clues on how to do so in buildings that were damaged, but still are standing. "Our objective in visiting ground zero was to go and look at the buildings surrounding the World Trade Center, those buildings that are still standing, but that sustained damage," said M. Bruneau, Ph.D. "Our immediate hope is that we can develop a better understanding as to why those buildings remain standing, while our long-term goal is to see whether earthquake engineering technologies can be married to existing technologies to achieve enhanced performance of buildings in the event of terrorist attacks," he added. Photographs taken by the investigators demonstrate in startling detail the monumental damage inflicted on the World Trade Center towers and buildings in the vicinity. One building a block away from the towers remains standing, but was badly damaged. "This building is many meters away from the World Trade Center and yet we see a column there that used to be part of that building", explained A. Whittaker, Ph. D. "The column became a missile that shot across the road, through the window and through the floor." The visit to the area also revealed some surprises, according to the engineers. For example, the floor framing systems in one of the adjacent buildings were quite rugged, allowing floors that were pierced by tons of falling debris to remain intact." Highly redundant ductile framing systems may provide a simple, but robust strategy for blast resistance," he added. Other strategies may include providing alternate paths for gravity loads in the event that a load-bearing column fails." We also need a better understanding of the mechanism of collapse, "said A. Whittaker. "We need to find out what causes a building to collapse and how you can predict it." A. Reinhorn, Ph.D. noted that "earthquake shaking has led to the collapse of many buildings in the past. It induces dynamic response and extremely high stresses and deformations in structural components. Solutions developed for earthquake-resistant design may be directly applicable to blast engineering and terrorist-resistant design. Part of our mission now at UB is to transfer these solutions and to develop new ones where none exist at present. "

单选题Only a small minority of the mentally ill are liable to harm themselves or others.

单选题A3XX will fly faster while consuming less oil.

单选题France"s renewal of the nuclear testing in the South Pacific last month triggered political debates and mass demonstration.

单选题Her behaviour is extremely childish .

单选题The weather is a constant {{U}}subject {{/U}} of conversation in Britain.

单选题Customers often {{U}}defer{{/U}} payment as long as possible.

单选题 Pop Music in Africa Young musicians in African countries are creating a new kind of pop music. The tunes and the rhythms of their music combine African traditions with various forms of music popular today, such as hip-hop, rap, rock, jazz or reggae. The result is music that may sound familiar to listeners anywhere in the world, but at the same time is distinctly African. It is different also in another way- Many of the songs are very serious and they deal with important social or political issues in Africa today. Eric Wainaina is one of these African musicians. He grew up in Nairobi, Kenya, in a family of musicians. As a teenager, he listened to pop music from the United States, and later he moved to Boston to study at the Berklee College of Music. Now he has produced a CD in Kenya. Eric's most popular song, "Land of 'A Little Something' " is about Kenya's problem of bribery, or paying others for illegal favors. He wants people to listen to his songs and think about how to make Kenya a better place to live. Another musician who writes serious songs is Witness Mwaijaga from Tanzania. Her own experiences have helped her understand the suffering of many African women. At the age of fifteen she lost her home, but she was luckier than other homeless young people. She could make a living by writing songs and singing on the street. By the time she was eighteen years old, she had become a star. Her songs are written in rap or hip-hop style about the problems that she sees in Tanzania, especially AIDS and the lack of rights for women. Baaba Maal, from Senegal, also feels that pop music must go beyond entertainment. He says that in Senegal, storytellers have always been important people. In the past, they were the ones who kept the history of their people alive. Baaba believes that songwriters now have a similar responsibility. They must write about the world around them and help people understand how it could be better. The words of his songs are important, in fact. They speak of peace and cooperation among Africans, as well as the rights of women, love for one's family, and saving the environment. One of South Africa's most popular musicians is Brenda Fassie. She is sometimes compared to Madonna, the American pop star, because she likes to shock people in her shows. But she also likes to make people think. She became famous in the 1980s for her simple pop songs against apartheid. Now that apartheid has ended, her songs are about other issues in South African culture and life. To sing about these, she uses local African languages and a new pop style called kwaito. In recent years, people outside of Africa have also begun to listen to these young musicians. Through music, the younger generation of Africans are connecting with the rest of the world and, at the same time, influencing the rest of the world.

单选题The soldier displayed remarkable courage in the battle.

单选题Pendulums are used to regulate motion in some scientific {{U}}equipments{{/U}}.

单选题He is in a rather difficult {{U}}situation{{/U}} at present.

单选题While some office jobs would seem boring to many people, there are quite a few jobs that are stimulating, exciting and satisfying.A. hostileB. tediousC. fantasticD. courageous

单选题Thousands of people perished in the storm.

单选题I don't why everything around me is going into confusion.A. considerationB. puzzleC. attractionD. contradiction

单选题While he was in prison, his guards Udeprived/U him of all luxuries.

单选题A Phone That Knows You"re Busy It"s a modern problem: you"re too busy to be disturbed by incessant (连续不断的) phone calls so you turn your cell phone off. But if you don"t remember to turn it back on when you"re less busy. You could miss some important calls if only the phone knew when it was wise to interrupt you, you wouldn"t have to turn it off at all. Instead, it could let calls through when you are not too busy. A bunch of behavior sensors (传感器) and a clever piece of software could do just that, by analyzing your behavior to determine if it"s a good time to interrupt you. If built into a phone, the system may decide you"re too busy and ask the caller to leave a message or ring back later. James Fogarty and Scott Hudson at Camegie Mellon University in Pennsylvania based their system oil tiny microphones, cameras and touch sensors that reveal body language and activity. First they had to study different behaviors to find out which ones strongly predict whether your mind is interrupted. The potential "busyness" signals they focused on included whether the office doors were left open or closed, the time of day, if other people were with the person in question, how close they were to each other, and whether or not the computer was in use. The sensors monitored these and many other factors while four subjects were at work. At random intervals, the subjects rated how interruptible they were on a scale ranging from "highly interruptible" to "highly not-interruptible". Their ratings were then correlated with the various behaviors. "It is a shotgun (随意的) approach: we used all the indicators we could think of and then let statistics find out which were important," says Hudson. The model showed that using the keyboard, and talking on a landline or to someone else in the office correlated most strongly with how interruptible the subjects judged themselves to be. Interestingly, the computer was actually better than people at predicting when someone was too busy to be interrupted. The computer got it right 82 per cent of the time, humans 77 per cent. Fogarty speculates that this might be because people doing the interrupting are inevitably biased towards delivering their message, whereas computers don"t care. The first application for Hudson and Fogarty"s system is likely to be in an instant messaging system, followed by office phones and cellphones. "There is no technological roadblock (障碍) to it being deployed in a couple of years," says Hudson.