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单选题A variety of significant, attractive short-term benefits will drive the development of modern self-sufficient homes. These include security from severe weather, climate changes, and natural disasters; security from infectious diseases and related health problems; a fresh and nutritious diet; a dependable food supply; and security from global unrest. But the real benefit of Earth Homes will be the long-term sustainability of our planet. It should be no secret that the planet is experiencing unusual weather and climate abnormalities. The 10 hottest years in recorded history have all been in the last 15 years; the 1990s were the hottest decade on record. The Midwestern heat wave of 1995 killed 669 people in Chicago. In 1996, we had a season of record heat spells, and 1997 was the single warmest year on record—until 1998 shattered global temperature records. Record-high temperatures throughout the southern United States during the summer of 1998 forced the shutdown of Walt Disney World's water parks because of the threat of a viral encephalitis outbreak. The United Nations and insurers blame unusual weather for thousands of deaths and billions of dollars in damage. Many scientists agree that the emissions resulting from human activities are substantially increasing the atmospheric concentration of the greenhouse gases. These increases will enhance the greenhouse effect, resulting in warming of the earth's surface. In 1990, scientists predicted that, if greenhouse gas emissions are not sharply decreased, we might experience a 1℃ to 3℃ rise in global temperatures. They suggested that we would have to cut in half our use of coal, oil, and gas in order to lower our emissions enough to maintain concentrations of greenhouse gases at the current levels. Proof of warming includes a decrease in the amount of snow that covers the Northern Hemisphere, a simultaneous decrease in Arctic Sea ice, continued melting of alpine glaciers, and a rise in sea level. Rain has even been reported for the first time in Antarctica, and an ice-free patch of ocean about a mile wide has recently opened near the North Pole. Meanwhile, studies have shown that the carbon dioxide concentration in our atmosphere has been steadily increasing since 1958. Even though the rate of emissions from fossil fuels has been reduced, concentration has risen consistently. In 1995, the size of the ozone hole over Antarctica doubled to about the size of Europe. For the first time in recorded history, the hole stretched over populated areas, exposing residents in southern Chile and Argentina to very high levels of ultraviolet (UV) radiation. Studies have shown that a 1% decrease in ozone in the stratosphere produces a 2% increase in UV radiation reaching the ground, posing more risks to humans.

单选题 Read the following text. Choose the best word for each numbered blank and mark A, B, C or D on ANSWER SHEET 1. Although the size of the workforce depends a great deal on the size of the total population, there are several other influences which also affect it. The age distribution of the total population has a very {{U}}(21) {{/U}} effect on the available workforce. If the population has a high {{U}}(22) {{/U}} of very young people or of {{U}}(23) {{/U}} too old to work, then the available workforce would be lower than {{U}}(24) {{/U}} there were an {{U}}(25) {{/U}} spread age distribution. If the population grows raidly {{U}}(26) {{/U}} natural increase, i.e., the number of births greatly {{U}}(27) {{/U}} the number of deaths, then as a total population increases the proportion of the workforce {{U}}(28) {{/U}}. Sometimes a population is described as aging, {{U}}(29) {{/U}} means that the birth rate is either falling or growing very slowly, and as people retire {{U}}(30) {{/U}} the workforce there are insufficient numbers of young people entering it to {{U}}(31) {{/U}} those who are leaving it. The population is top heavy with older people. So the {{U}}(32) {{/U}} of the population in the workforce declines when there is {{U}}(33) {{/U}} a rapid increase in births or a falling birth rate. The age distribution of the population has several important effects on the economy. If the population is aging and there is an increase in the number of people retiring {{U}}(34) {{/U}} a corresponding increase in the number entering the workforce, this raises the problem of the ability of the economy to provide a {{U}}(35) {{/U}} level of social services to the retired group. If the {{U}}(36) {{/U}} are to be cared {{U}}(37) {{/U}} in special homes or hotels, finance must be {{U}}(38) {{/U}} for that purpose. If the size of the workforce is small relative {{U}}(39) {{/U}} the total population, then the government tax receipts are relatively low and either the government has less money available to it or the workforce members have to be {{U}}(40) {{/U}} more heavily.

单选题Whenabonebendsbutdoesnotbreak,itiscalled______.A.ahairlinefractureB.acomminutedfractureC.abowingfractureD.anopenfracture

单选题Plastics are materials which are softened by heat and set into lasting form when shaped in a mold. Some are natural; some are semi synthetics as the result of chemical action on a natural substance; some are synthetic, built up from the constituents of oil or coal. All are based on the chemistry of carbon, with its capacity for forming chains. The molecules that compose them (monomers) link together in the setting or curing process to form chains (polymers), which give plastics their flexible strength. Some plastics retain their ability to be softened and reshaped; like wax, they are thermoplastic. Others set permanently in the shapes they are given by heat and pressure; like eggs, they are thermosetting. From industrial beginnings in the 19th century, plastics have struggled through a 120 years of glory, failure, disrepute and suspicion on the slow road to public acceptance. Now, at last, one can positively say that plastics are appreciated and enjoyed for what they are; that they make modern life richer, more comfortable and convenient and also more funny. Plastics are warm materials, sympathetic to the human touch and their transformation into things that come into contact with human beings is entirely appropriate. The fact that there are plastics antiques comes as a shock to most people. How can a material that seems so essential in the 20th century, and one that is so much associated with cheap disposable products, have a history at all? It is a young technology, and a great pan of the fun of collecting plastics is that beautiful pieces of historical interest can still be found very cheaply.

单选题Whataretheygoingtodo?A.Theyaregoingshopping.B.Theyaregoingtoeatout.C.Theyaregoingtohaveawalk.

单选题Questions 17-20 are based on a report about generation gap. You now have 20 seconds to read Questions 17-20.

单选题In the last sentence of the passage, the word "confinement" is closest in meaning to the word" ______ ".

单选题I know something about Kunming. I ______ there many times. [A] have gone [B] have been [C] went

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单选题What is the main point the author makes in the passage?

单选题Besides climate change, developing countries like China need to deal with energy 1 and environmental issues: the development of sources of clean energy needs to be 2 line with their interests. Clean energy has been given greater prominence than ever before; it is seen as a new industrial 3 and 4 of economic growth for the new century. The time for clean energy has come. In China, clean energy is moving ahead at full speed. Take wind power as an example: by the end of last year, China had 5 wind power generating capacity of 12.21 GW, making China the largest wind power generator in Asia and first in the world. But according to the research, one-third of wind power capacity is running 6 due to an inability to get the power to the national 7 . India-like China—relies 8 on coal for its energy needs. This will only change if the funds and technology to develop clean energy, such as wind and nuclear power, are 9 . India will not choose clean energy 10 , Nuclear power is currently the most 11 of clean energy sources. 12 , if it is to be 13 on a large scale by developing nations, technological advances will be needed to make it competitive with coal. Compared 14 developed countries, developing countries have more 15 choices when it comes to energy structure. Promoting economic growth requires 16 energy—and coal, the cheapest and most 17 source of energy for many countries—is the 18 choice. Cheap coal means cheap electricity and a competitive economy. Rising electricity prices would cause public 19 and impact on standards of 20 .

单选题According to the article, communication problems arise when

单选题 Questions 11～13 are boxed on a piece of news about college admission in the USA. Yon now have 15 seconds to read Questions 11～13.

单选题Before the sales start, I make a list of ______ my kids will need for the coming season. A. where B. which C. what D. how