题目内容
The Differences in Living Standards
The differences in living standards around the world are vast. In 1993, the average American had an income of about $25,000. In the same year, the average Mexican earned $7,000, and the average Nigerian earned $1,500. Not surprisingly, this large variation in average income is reflected in various measures of the quality of life. Changes in living standards over time are also large. In the United States, incomes have historically grown about 2 percent per year (after adjusting for changes in the cost of living). At this rate, average income doubles every 35 years. In some countries, economic growth has been even more rapid. In Japan, for instance, average income has doubled in the past 20 years, and in South Korea it has doubled in the past 10 years.
What explains these large differences in living standards among countries and over time？ The answer is surprisingly simple. Almost all variation in living standards is attributable to differences in countries&39; productivity- that is, the amount of goods and services produced from each hour of a worker&39;s time. In nations where workers can produce a large quantity of goods and services per unit of time, most people enjoy a high standard of living; in nations where workers are less productive, most people must endure a more meager existence. Similarly, the growth rate of a nation&39;s productivity determines the growth rate of its average income.
The fundamental relationship between productivity and living standards is simple, but its implications are far-reaching. If productivity is the primary determinant of living standards, other explanations must be of secondary importance. For example, people might think that labor unions or minimum-wage laws contributed to the rise in living standards of American workers over the past century. Yet the real hero of American workers is their rising productivity.
The relationship between productivity and living standards also has great implications for public policy. When thinking about how any policy will affect living standards, the key question is how it will affect our ability to produce goods and services. To improve living standards, policy makers need to raise productivity by ensuring that workers are well educated, have the tools needed to produce goods and services, and have access to the best available technology.
Which of the following countries has enjoyed the fastest economic growth in history？ 查看材料
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More Than 8 Hours Sleep Too Much of a Good Thing
(1) Although the dangers of too little sleep are widely known, new research suggests that people who sleep too much may also suffer the consequences.
(2) Investigators at the University of California in San Diego found that people who clock up 9 or 10 hours each weeknight appear to have more trouble falling and staying asleep, as well as a number of other sleep problems, than people who sleep 8 hours a night. People who slept only 7 hours each night also said they had more trouble falling asleep and feeling refreshed after a night&39;s sleep than 8-hour sleepers.
(3) These findings, which Dr. Daniel Kripke reported in the journal Psychosomatic Medicine,demonstrate that people who want to get a good night&39;s rest may not need to set aside more than 8 hours a night. He added that "it might be a good idea" for people who sleep more than 8 hours each night to consider reducing the amount of time they spend in bed, but cautioned that more research is needed to confirm this.
(4) Previous studies have shown the potential dangers of chronic shortages of sleep- for instance, one report demonstrated that people who habitually sleep less than 7 hours each night have a higher risk of dying within a fixed period than people who sleep more.
(5) For the current report, Kripke reviewed the responses of 1,004 adults to sleep questionnaires,in which participants indicated how much they slept during the week and whether they experienced any sleep problems. Sleep problems included waking in the middle of the night,arising early in the morning and being unable to fall back to sleep, and having fatigue interfere with day-to-day functioning5.
(6) Kripke found that people who slept between 9 and 10 hours each night were more likely to report experiencing each sleep problem than people who slept 8 hours. In an interview,Kripke noted that long sleepers may struggle to get rest at night simply because they spend too much time in bed. As evidence, he added that one way to help insomnia is to spend less time in bed. "It stands to reasons6 that if a person spends too long a time in bed, then they&39;ll spend a higher percentage of time awake," he said.
Paragraph 2 __________ 查看材料
A Record-Breaking Rover
NASA&39;s Mars rover Opportunity has boldly gone where no rover has gone before-- at least in terms of distance. Since arriving on the Red Planet in 2004, Opportunity has traveled 25.01 miles, more than any other wheeled vehicle has on another world. On July 27, after years of moving about on Martian ground, the golf-cart:sized Opportunity had driven more than 24 miles, beating the previous record holder--a Soviet rover sent to the moon in 1973.
"This is so remarkable considering Opportunity was intended to drive about 1 kilometer and was never designed for distance," says John Callas, the Mars Exploration Rover Project Manager.
He works at NASA&39;s Jet Propulsion Laboratory in Pasadena, California. "But what is really important is not how many miles the rover has racked up, but how much exploration and discovery we have accomplished over that distance."
Opportunity
The solar-powered Opportunity and its twin rover, Spirit, landed on Mars I0 years ago on a mission expected to last 3 months. The objective of the rovers was to help scientists learn more about the planet and to search for signs of life, such as the possible presence of water.
Spirit stopped communicating with Earth in March 2010, a few months after it got stuck in a sand pit. But Opportunity has continued to collect and analyze Martian soil and rocks.
During its mission, Opportunity has captured, and sent back to Earth, some 187,000 panoramic and microscopic images of Mars with its cameras. It has also provided scientists with data on the planet&39;s atmosphere, soil, rocks, and terrain.
Marathon Rover The rover doesn&39;t seem to be ready to stop just yet. If Opportunity can continue on, it will reach another major investigation site when its odometer hits 26.2 miles. Scientists call this site Marathon Valley, because when the rover reaches the area, it will have traveled the same distance as the length of a marathon since its arrival on Mars.
Researchers believe that clay minerals exposed near Marathon Valley could hold clues to Mars&39;s ancient environment. Opportunity&39;s continuing travels will also help researchers as they plan for an eventual human mission to the Red Planet.
Opportunity is a record-breaking rover in the sense of __________. 查看材料
根据下列材料，请回答下面的题目：
2012年我国夏粮生产获得了较好收成。全国夏粮总产量达到12995万吨，比201 1年增加356万吨，增长2．8％，超过l997年12768万吨的历史最高水平，比10年前增长31．6％。2012年，河北、山西、江苏、安徽、山东、河南、湖北、四川、陕西、甘肃、新疆这11个主产省(区)增产夏粮364万吨，其中安徽增产80万吨、山东增产75万吨、河北增产63万吨、河南增产55万吨．在非主产省(市、区)中北京、辽宁、浙江、湖南、重庆、云南、宁夏有不同程度减产。
2007～2012年全国夏粮产量
2012年11个主产省(区)夏粮播种面积及总产量
2002年全国夏粮产量约为：
说 明：根据下列内容写一分电子邮件
发件人：李林
收件人：林伟
日 期：2006年12月15日，星期日，9:30
内 容：打算去英国剑桥大学学习，想了解中国学生在英国学习的情况。
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Dear Lin Wei,
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