单选题1 Play is common to the young of most mammals. Some birds play, but it is rare in cold-blooded animals such as fish and reptiles. Why some animals play, and others do not, is not entirely understood, but the most playful--such as dolphins and monkeys--are also the most intelligent and sociable. Play may seem something of a puzzle. Not only is it apparently unproductive, but it also places the participant at risk of being surprised by predators. However, there must be a good reason for play. The most widely held scientific explanation is that play allows the social behaviors of the species to be explored and learned. Other benefits include physical exercise and the learning of survival skills such as hunting. A kitten that grows up separated from other kittens becomes both a social misfit and a poor hunter, largely because it is deprived of play. 2 Kittens start playing when they are about three weeks old. Early play consists of mock attacks with the mother and littermates, clearly previewing the territorial behavior of adult life. As the kittens grow older, more elaborate play patterns develop. At four weeks they can wrestle. The sideways leap and the pounce may be learned by the fifth week. By six weeks they can chase and leap on each other with reasonable accuracy. Kittens stalk, chase, and fall over each other. They recognize these patterns as being playful, even though the same signals in adult life may have a more serious meaning.

单选题The Fashion Style of the 1990s The last decade of the "90s has made a big fashion statement with the introduction of the urban grunge style. Because grunge was so predominant throughout the mid-nineties, it is often mistakenly assumed that the "90s is an era of anti-fashion. Nothing could be further from the truth, however. The closing decade of the previous century is in fact an amalgam of very different, if not contradictory fashion trends and styles, Innovative hippie trends mix harmoniously with the retro style of the "60s and "70s. The rather pretentious style of the "80s flows seamlessly into the laid back alternative grunge culture. Minimalist fashion goes hand in hand with the trendy over-the-top disco style of the outgoing era. The booming fitness industry puts its mark on the fashion industry as well by turning sportswear into stylish outfits. The early "90s is still dominated by trends popular in the late "80s. Acid-washed denim, jackets and slim fit jeans are still the rage up until 1994, but slowly go into decline to be replaced by more relaxed cuts and varying shades of stonewashed denim. Denim is mainly worn with black or white T-shirts, although the hippie dye shirts of the "60s crop up quite frequently as well. The heavy hair-sprayed coiffure of the "80s relaxes as well in favor of the more natural look conferred by long straight hair with bangs in women and the bowl cut in men. The biggest fad of this period, however, is the emergence of fluorescent colored clothing. Anything from sweatshirts and shoelaces to hair scrunchies and pouch bags glimmer in brilliant corals and turquoise. Inspired by the newly developing gym and fitness culture, adolescents and young adults also favor cropped tank tops, biker tights and tracksuits made of spandex. As far as accessories go, hoop earrings, round granny style shades and baseball caps are an absolute must. The main fashion style popularized by the "90s was grunge. Grunge evolved from the underground dark music played in seedy Seattle locals by such artists as the late Kurt Cobain. Disgusted by what he perceived as the forced cheerful pink look of the "fluorescent generation," Cobain turned to earthier and darker colors like indigo, maroon and forest green. The under-accentuated unisex Grunge look entered the mainstream fashion market with the adoption of the plaid flannel shirt and the hooded sweatshirt. It also favored the long flailing hairstyle that got into the eye and covered the face. which went very well with the moody melancholic philosophy prevalent amongst youngsters during that time. Grunge adopted several items of the late hippie look, such as the crocheted vest and bell-bottom jeans of the "70s, which complemented the rebellious grungers very well. Another fashion item popularized by the Grunge look were the dark heavy Doc Martens boots and high top black running shoes of Nike Air Jordans, as well as the sagging dark jeans worn by boys and girls alike. As a matter of fact, fashionistas of the mid "90s continued to be inspired by sports celebrities and rap musicians, and many youngsters began to don baseball or basketball jerseys and wear their caps backwards. The unisex monochromatic Grunge slowly went into decline to be replaced by the red Guess and Mod styles in 1995. The revival of the Mod style coincided with a navel piercing fad that led to the wearing of belly shirts and low cut jeans that exposed the midriff area. Girls also favored Capri pants and spaghetti strap tank tops to further show off their cleavage. Trendy stilettos, minis and wraparound skirts, as well as tight fitting baby doll T-shirts in pink, baby-blue and plum made their way from the small screen into the living room of teenage and college girls, who sought to imitate the look of their favorite movie stars Sarah Jessica Parker or Reese Witherspoon. The most enduring influence would be that of TV actress Jennifer Anniston, who revived Farrah Fawcett"s layered shaggy haircut and turned it into a fashion icon. Anniston"s character, Rachel Green, from the hit-TV sitcom Friends lent this new look its name, and the "Rachel" hairstyle is still dominant with slight variations in the fashion world today. As far as the male factor is concerned, certain grunge elements still persist during the late "90s in the form of golf and polo shirts, as well as skater shoes, while the granny style sunglasses and bowl cut are history. Boys and men alike prefer spiky short hair dyed blond and wraparound shades as promoted by the "preppy look" of Tommy Hilfiger and Tiger Woods. Very popular are khakis and camouflage pants, too. Glossary grunge style: the name of a fashion and of a type of music tank top: a close-fitting, low-cut top having shoulder straps cleavage: the space between the breasts

单选题Energy In industrialized nations, people are using more and more energy all the time so that its demand is ever increasing. Practically everything we do, from talking on the phone to driving to work and heating up our lunch, it all requires energy. Most of this energy comes from fossil fuels, but the problem is that fuels like coal, oil and natural gas are non-renewable, and burning fossil fuels also releases chemicals into the air that damage the environment and pose a serious risk to public health. Fossil fuels are found in deposits beneath the earth; they are the result of decayed plants and animals buried in rock that over time have become fossilized. Time and pressure gradually turned those fossilized organic deposits into coal, oil and natural gas. The energy demand and usage have risen sharply over the last thirty years and are only set to further increase. Emissions released due to the burning of fossil fuels are harmful to the environment, and the only way to reduce emissions is to switch to low carbon alternatives. Alternative renewable energy sources include wind and solar power both of which are abundant non-polluting and sustainable energy resources. People are increasingly turning to such renewable sources although they still very, much rely on fossil fuels. Oil, gas and coal are used to generate electricity in power stations. Gas can be extracted directly from wet natural gas or can be obtained as a by-product of the petroleum refining process. As well, the amount of energy people use for their everyday lives has increased dramatically, but the amount of energy used by industry has decreased because of fewer energy intensive industries and better energy efficiency. The main environmental impact of burning fossil fuels comes from the emission of greenhouse gases. Scientists agree that greenhouse gases are the major source of climate change, which is otherwise known as global warming. Oil spillages from oil refineries and drilling sites are also a major cause of environmental pollution. The damage caused by harvesting and burning fossil fuels can be seen in the pollution of water flowing through coal mines. This in turn contaminates other water sources. Methane gas leaking from pipe lines and coal mines further contributes to the greenhouse effect. Exhaust gases from vehicles emit substances such as nitrogen dioxide and greatly affect public health, especially those suffering from asthma. In addition to carbon dioxide, burning fossil fuels also releases other gases, such as sulphur dioxide, into the atmosphere, increasing the greenhouse effect and causing acid rain, thus heavily polluting the air in those urban areas in which their concentrations are normally highest. World total fossil energy demand is expected to increase even faster than today in the not fat distant future because of accelerated economic development by the newly emerging industrial nations, such as China and India. It will not be easy to change the way nations supply and use energy but what is certain is that changing to renewable energy sources will greatly reduce greenhouse gas emissions. Moreover, the efficient management of renewable sources and the radical reduction of pollution cannot be achieved without the formulation of and commitment to long term plans. Glossary emission: substances and especially pollutants discharged into the air alternative: something which can be chosen instead fossil fuel: fuel consisting of the remains of organisms preserved in rocks in the earth"s crust with high carbon and hydrogen content exhaust: the release of vaporous waste material, as from an engine sustainability: ability to keep in existence

单选题The word "resumed" in line 7 is closest in meaning to

单选题The rings of the planet Uranus consists primarily of boulder-sized chunks of dark matter, averaging about one meter in diameter

单选题The Liberty Bell, formerly housed in Independence Hall, _____in Philadelphia, was moved to a separate glass pavilion in 1976.

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单选题According to the passage, what is one difference between the hunting done by some humans and the hunting done by gray wolves?

单选题Architecture is concerned with the large-scale manipulation of elements in the dimensions of length, width, and height. These dimensions may apply to a solid, such as the Egyptian pyramids, or to hollow interior spaces, ranging in size and complexity from a domestic room to a vast cathedral. They may also apply to the spaces around and between buildings. Moreover, every building has a physical context in relation to other buildings. Sometimes the designer disregards the context on the assumption that surrounding structures will later be replaced. However, it is more often posterity that destroys the once appropriate original context. 3. Which sentence below best expresses the essential information in the highlighted sentence in the passage?

单选题(Heat) exhaustion is (causing) by excessive (loss) of body (fluids) and body salts.

单选题Toward the end of his life, John Singer Sargent returned to the painting of landscapes and the use of watercolors, of which he excelled.

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单选题The word "accumulated" in line 6 is closest in meaning to

单选题Taste buds, small sensory organ located on the tongue and palate, recognize four primary tastes: sweet, sour, salty and bitter.

单选题Which of the following is NOT mentioned in paragraph 1 as resulting from rapid ecological change?

单选题Which of the following statements is supported by the information in paragraph 1 ? (a) All government policy makers accepted Jefferson's views of agriculture and farmers. (b) Agricultural production declined between 1782 and 1861. (c) The majority of farmers worked for the government. (d) Agriculture was a vital part of the nation's economy.

单选题Generally, the representatives ______a legislature are constitutionally elected by a broad spectrum of the population. A. who they compose B. who compose C. ad compose D. compose

单选题The flowering of African American talent in literature, music, and art in the 1920’s in New A B C York City became to know as the Harlem Renaissance. D

单选题Listening4"CollegeCampus"

单选题The Expressionistic artist was concerned not with the reality of the subject matter but with— inner nature and the emotions that it aroused