单选题His office is ______ to the President's; it usually takes him about three minutes to get there.

单选题If you want to become a doctor, you ought to study ______.

单选题The Jewish New Year most probably comes between ______.

单选题 Elite Math Competitions Struggle to Diversify Their Talent Pool A. Interest in elite high school math competitions has grown in recent years, and in light of last summer's U.S. win at the International Math Olympiad (IMO)—the first for an American team in more than two decades-the trend is likely to continue. B. But will such contests, which are overwhelmingly dominated by Asian and white students from middle-class and affluent families, become any more diverse? Many social and cultural factors play roles in determining which promising students get on the path toward international math recognition. But efforts are in place to expose more black, Hispanic, and low-income students to advanced math, in the hope that the demographic pool of high-level contenders will eventually begin to shift and become less exclusive. C. 'The challenge is if certain types of people are doing something, it's difficult for other people to break into it,' said Po-Shen Loh, the head coach of last year's winning U.S. Math Olympiad team. Participation grows through friends and networks and if 'you realize that's how they're growing, you can start to take action' and bring in other students, he said. D. Most of the training for advanced-math competitions happens outside the confines of the normal school day. Students attend after-school clubs, summer camps, online forums and classes, and university-based 'math circles,' to prepare for the competitions. E. One of the largest feeders for high school math competitions—including those that eventually lead to the IMO—is a middle school program called MathCounts. About 100,000 students around the country participate in the program's competition series, which culminates in a national game-show-style contest held each May. The most recent one took place last week in Washington, D.C. Students join a team through their schools, which provide a volunteer coach and pay a nominal fee to send students to regional and state competitions. The 224 students who make it to the national competition get an all-expenses-paid trip. F. Nearly all members of last year's winning U.S. IMO team took part in MathCounts as middle school students, as did Loh, the coach. 'Middle school is an important age because students have enough math capability to solve advanced problems, but they haven't really decided what they want to do with their lives,' said Loh. 'They often get hooked then.' G. Another influential feeder for advanced-math students is an online school called Art of Problem Solving, which began about 13 years ago and now has 15,000 users. Students use forums to chat, play games, and solve problems together at no cost, or they can pay a few hundred dollars to take courses with trained teachers. According to Richard Rusczyk, the company founder, the six U.S. team members who competed at the IMO last year collectively took more than 40 courses on the site. Parents of advanced-math students and MathCounts coaches say the children are on the website constantly. H. There are also dozens of summer camps—many attached to universities—that aim to prepare elite math students. Some are pricey—a three-week intensive program can cost $4,5000r more—but most offer scholarships. The Math Olympiad Summer Training Program is a three-week math camp held by the Mathematical Association of America that leads straight to the international championship and is free for those who make it. Only about 50 students are invited based on their performance on written tests and at the USA Math Olympiad. I. Students in university towns may also have access to another lever for involvement in accelerated math: math circles. In these groups, which came out of an Eastern European tradition of developing young talent, professors teach promising K-12 students advanced mathematics for several hours after school or on weekends. The Los Angeles Math Circle, held at the University of California, Los Angeles, began in 2007 with 20 students and now has more than 250. 'These math circles cost nothing, or they're very cheap for students to get involved in, but you have to know about them,' said Rusczyk. 'Most people would love to get students from more underserved populations, but they just can't get them in the door. Part of it is communication; part of it is transportation.' J. It's no secret in the advanced-math community that diversity is a problem. According to Mark Saul, the director of competitions for the Mathematical Association of America, not a single African-American or Hispanic student—and only a handful of girls—has ever made it to the Math Olympiad team in its 50 years of existence. Many schools simply don't prioritize academic competitions. 'Do you know who we have to beat?' asked Saul. 'The football team, the basketball team—that's our competition for resources, student time, attention, school dollars, parent efforts, school enthusiasm.' K. Teachers in low-income urban and rural areas with no history of participating in math competitions may not know about advanced-math opportunities like MathCounts—and those who do may not have support or feel trained to lead them. L. But there are initiatives in place to try to get more underrepresented students involved in accelerated math. A New York City-based nonprofit called Bridge to Enter Mathematics runs a residential summer program aimed at getting underserved students, mostly black and Hispanic, working toward math and science careers. The summer after 7th grade, students spend three weeks on a college campus studying advanced math for seven hours a day. Over the next five years, the group helps the students get into other elite summer math programs, high-performing high schools, and eventually college. About 250 students so far have gone through the program, which receives funding from the Jack Kent Cooke Foundation. M. 'If you look at a lot of low-income communities in the United States, there are programs that are serving them, but they're primarily centered around 'Let's get these kids' grades up,' and not around 'let's get these kids access to the same kinds of opportunities as more-affluent kids,'' said Daniel Zaharopol, the founder and executive director of the program. 'We're trying to create that pathway.' Students apply to the program directly through their schools. 'We want to reach parents who are not plugged into the system,' said Zaharopol. N. In the past few years, MathCounts added two new middle school programs to try to diversify its participant pool—the National Math Club and the Math Video Challenge. Schools or teachers who sign up for the National Math Club receive a kit full of activities and resources, but there's no special teacher training and no competition attached. O. The Math Video Challenge is a competition, but a collaborative one. Teams of four students make a video illustrating a math problem and its real-world application. After the high-pressure Countdown round at this year's national MathCounts competition, in which the top 12 students went head to head solving complex problems in rapid fire, the finalists for the Math Video Challenge took the stage to show their videos. The demographics of that group looked quite different from those in the competition round—of the 16 video finalists, 13 were girls and eight were African-American students. The video challenge does not put individual students on the hot seat—so it's less intimidating by design. It also adds the element of artistic creativity to attract a new pool of students who may not see themselves as 'math people.'

单选题Thousands of years ago man used handy rocks for his surgical operations. Later he used sharp bone or horn, metal knives and more recently, rubber and plastic. And that was where we stuck, in surgical instrument terms, for many years. In the 1960s a new tool was developed, one which was, first of all, to be of great practical use to the armed forces and industry, but which was also, in time, to revolutionize the art and science of surgery. The tool is the laser and it is being used by more and more surgeons all over the world, for a very large number of different complaints. The word laser means: Light Amplification by Stimulated Emission of Light. As we all know, light is hot; any source of light ——from the sun itself down to a humble match burning ——will give warmth. But light is usually spread out over a wide area. The light in a laser beam, however, is concentrated. This means that a light with no more power than that produced by an ordinary electric light bulb becomes intensely strong as it is concentrated to a pinpoint-sized beam. Experiments with these pinpoint beams showed researchers that different energy sources produce beams that have a particular effect on certain living cells. It is now possible for eye surgeons to operate on the back of the human eye without harming the front of the eye, simply by passing a laser beam right through the eyeball. No knives, no stitches (刀口缝合), no unwanted damage ——a true surgical wonder. Operations which once left patients exhausted and in need of long periods of recovery time now leave them feeling relaxed and comfortable. So much more difficult operations can now be tried. The rapid development of laser techniques in the past ten years has made it clear that the future is likely to be very exciting. Perhaps some cancers will be treated with laser in a way that makes surgery not only safer but more effective. Altogether, tomorrow may see more and more information coming to light on the diseases which can be treated medically.

单选题Thousands of people ______ from Greece every year to work in West Germany.

单选题(2004)____quite capable of working out this problem.

单选题She decided to take a second course since she ______the first one.

单选题______ you go there early, there won't be much a chance of getting a ticket.

单选题I disagreed fundamentally with what the sign ______.

单选题I've not read the first chapter, ______ finished the book.

单选题Reading ______ the lines, this letter is really a request for money.

单选题Whether their football team will win is a matter of ______ to me.

单选题Now many manufacturers build their business reputations by enclosing ______ in the new products in case of damage in shipment or by incorrect operation. A. categories B. accessories C. analogies D. observatories

单选题My wife would rather we ______ each other any more.

单选题John complained to the bookseller that there were some pages ______ in the dictionary.

单选题Research should continue on controlled nuclear fusion, but no energy program should be premised on its existence until it has proved practical.

单选题America"s Federal Reserve cut interest rates by another quarter-point, to 3.75 %. Wall Street, which had been 21 for a sixth half-point cut, was disappointed. The Dow fell by 2% 22 the week. The past week"s economic statistics gave mixed signals. Exports dropped by 2% in both March and April, largely 23 a decline in high-tech investment 24 ;the merchandise-trade 25 widened to $ 458 billion in the 12 months 26 April. 27 ,the Conference Board"s index of consumer confidence was higher than 28 in June. Concerns 29 inflation in the Euro area 30 . Preliminary data 31 that German consumer price inflation fell to 3. 1% in the year to June, from 3.5 % in May; wage growth 32 to 1.4% in April, a real pay cut of 1.5%. Some economists fear that Germany is on the 33 of recession. The IFO index of business confidence dropped more 34 than expected in May, and the institute has cut its forecast of GDP 35 this year to only 1.2% ,well below the German government"s forecast of 2%.

单选题All her hard work ______ in the end, and she finally passed the exam. A. showed off B. paid off C. left off D. kept off