单选题For a large number of young adults in Britain, homeownership has become increasingly difficult to achieve, viewed as a distant goal attainable only later in life, if at all. That is a significant shift for Britain. For years owners occupy a higher percentage of homes in Britain than in the United States, France or Germany. One reason homeownership is so attractive in Britain is because property values dropped less drastically than in the United States, in part because of a shortage in housing. Prices in some large cities, including London, have even increased recently. People still perceive a home to be a better and safer investment than a pension fund, said Andrew Hull, research fellow at the Institute for Public Policy Research. "Homeownership is also culturally entrenched, " he said. "Owning a home is the main way of showing you made it. " The big shift toward homeownership came in the 1980s when Mrs. Thatcher issued right-to-buy policy, which allowed many in rented government housing to buy their homes. About two million homes were sold, earning the government tens of billions of pounds. At the same time, the rental market became increasingly unattractive. Unlike Germany and other Continental European countries, Britain's private rental market is highly fragmented, with many landlords and laws that generally favor the property owner. Most leases are for six months only, with landlords rarely agreeing to commit to longer terms; this makes renting highly insecure. But as the pain of government-imposed austerity sinks in, disposable income has shrunk and loan requirements have toughened , forcing more and more Britons into renting rather than buying. Over the last 10 years the number of people who owned homes here dropped to 67 percent from 70 percent. Meanwhile, the number of people in private rented housing rose to 16 percent from 10 percent over the same period, according to the Office for National Statistics. Rising demand has pushed up rents by an average of 4.4 percent over the last year, according to LSL Property Services. In London rents increased 7.8 percent. "A growing number of young would-be buyers are preparing for lifelong renting—by necessity rather than choice, " said Jonathan Moore, director of easy roommate, co. uk, a property Web site. Charlotte Ashton, 30, has lived in rented accommodations ever since she left her parent's home to attend university. She said she was saving for a down payment to buy her own home. "I do believe in the fundamentals of owning bricks and mortar as security for the future, more than leaving my money in the banks at a low interest rate, " said Ms. Ashton, who works in public relations. "But now it seems unless you have a very well paid job and are willing to save every penny, it's unfeasible to buy without the help of the bank of Mum and Dad. " Some economists are concerned that as more people are forced to wait to buy a home, it could open up a widening of the wealth gap that already exists between homeowners and non homeowners, endangering the retirement prospects for a swelling group of young adults they call "generation rent. " It could also have implications for the cohesion of neighborhoods, Alison Blackwell, a research director at the National Center for Social Research and author of the Halifax report said. Renters tend to be less involved in local communities because they are forced to move more often. And the economy as a whole may suffer because renters tend to curb spending to save for a deposit.

单选题The Celts helped France to resist

单选题What is the writer's opinion concerning courteous manners toward women?

单选题Speaking of the rising egg consumption, the author implies the dominant factor accounting for this is that

单选题People, like most animals, are naturally lazy. So the ascent of mankind is something of a mystery. Humans who make their livings hunting and gathering in the traditional way do not have to put much effort into it. Farmers who rely on rain to water their crops work significantly harder, and lead unhealthier lives. But the real back-breaking is that carried out by farmers who use irrigation. Yet it was the invention of irrigation, at first sight so harmful to its practitioners that actually produced a sufficient surplus to feed the priests, scholars, artists and so on whose activities are collectively thought of as "civilization". In the past 10,000 years, the world's climate has become temporarily colder and drier on several occasions. The first of these, known as the Younger Dryas, after a tundra-loving plant that thrived during it, occurred at the same time as the beginning of agriculture in northern Mesopotamia. It is widely believed that this was not a coincidence. The drying and cooling of the Younger Dryas adversely affected the food supply of hunter-gatherers. That would have created an incentive for agriculture to spread once some bright spark invented it. Why farmers then moved on to irrigation is, however, far from clear. But Harvey Weiss, of Yale University, thinks he knows. Dr. Weiss observes that the development of irrigation coincides with a second cool, dry period, some 8,200 years ago. His analysis of rainfall patterns in the area suggests that rainfall in agriculture's upper-Mesopotamian heartland would, at this time, have fallen below the level needed to sustain farming reliably. Farmers would thus have been forced out of the area in search of other opportunities. Once again, an innovative spark was required. But it clearly occurred to some of these displaced farmers that the slow-moving waters of the lower Tigris and Euphrates, near sea level, could be diverted using canals and used to water crops. And the rest, as the cliche has it, is history. So climate change helped to intensify agriculture, and thus start civilization. But an equally intriguing idea is that the spread of agriculture caused climate change. In this case, the presumed criminal is forest clearance. Most of the land cultivated by early farmers in the Middle East would have been forested. When the trees that grew there were cleared, the carbon they contained ended up in the atmosphere as carbon dioxide. Moreover, one form of farming—the cultivation of rice in waterlogged fields—generates methane, in large quantities. William Ruddiman, of the University of Virginia, explained that, in combination, these two phenomena had warmed the atmosphere prior to the start of the industrial era. As environmentalists are wont to observe, mankind is part of nature. These studies show just how intimate the relationship is.

单选题{{B}}Text 3{{/B}} When stars like our Sun die, they bloat to become red giants and then eject gigantic clouds of gas and dust into space. Increasingly, however, scientists found themselves at a profound loss to explain how exactly dying stars could blow away these clouds. Now astrophysicists propose that unexpected chemical reactions during the formation of stardust could help solve this mystery. Stars smaller than the Sun and up to eight times as massive die by swelling up into red giants before shedding most of their mass to shrink into very compact, dying embers (灰烬) called white dwarfs. Two kinds of red giants exist-those with lots of carbon, and others richer in oxygen than in carbon. Carbon-rich stars release carbon particles during their death throes. Scientists proposed these pitch-black grains absorb rays from the dying star and get shot into space by starlight, a theory that fit both the observations and computer models. Increasingly, however, researchers could not explain how oxygen-rich stars like our own Sun could propel their clouds away during the final stages of mass loss. Oxygen-rich stars create large quantities of water vapor and silicates, such as quartz (石英砂) or sand. These are transparent, meaning starlight should go right through them. Possible solutions have been contemplated by scientists. They first pondered whether the silicates might have iron in them, which would render them opaque instead of transparent. But calculations showed the dust grains would have evaporated if they had iron in them. They next wondered if enough molecules surrounded the core of a dying oxygen-rich star to block out its light and thus create a wind that blew the star's outermost layer into space. But their models suggested these molecules could not block off enough light and create strong enough Rinds. The scientists then suggested that pulsations occurred when stars die could perhaps force a star's matter out, but this idea did not match with astronomers' observations. But inspiration then dawned upon them. Perhaps some of the carbon in the oxygen-rich stars could help force the outer layers of the stars into space. They believe shock waves from the pulsations of dying stars could make carbon in oxygen-rich stars form pitch-black dust. "The theory fits with all our subsequent model calculations, and it matches observations from dying oxygen-rich red giants". Moreover," this mechanism strongly favors the presence of magnesium silicates over iron silicates in the interstellar medium," in agreement with recent findings from NASA's comet-sampling Stardust space probe. If proven correct, the beauty of the new scenario is that it suggests a common driving mechanism for many dying stars shedding their mass via dusty winds," with possible long-reaching consequences for the origin of chemical elements relevant for life."

单选题{{B}}Text 2{{/B}} Kevin Hines, a manic-depressive, was 19 and in one of his weekly downswings on an overcast Monday morning in 2000. He went to the nearby Golden Gate Bridge to kill himself mostly because, with only a four-foot (1.2-metre) railing to leap, "I figured it was the easiest way." He dived over, but flipped and hit the water at 75mph with his feet first. His legs were crushed, but he somehow stayed conscious and started paddling with his upper body until the Coast Guard fished him out. Mr. Hines is one of 26 people who have survived suicide attempts at the bridge, but 1 223 are known to have succeeded (i. e., were seen jumping or found floating). People are throwing themselves off the bridge at the rate of two a month, which makes it the most popular place in the world for suicides. One book on the subject says that the Golden Gate is "to suicide what Niagara Falls is to honeymooners". Many San Franciscans think that the solution is to emulate the Empire State Building, the Sydney Harbour Bridge, the Eiffel Tower, St. Peter's basilica and other such places and put up a simple barrier. This, however, is a decision for the 19 board members of the Golden Gate Bridge, Highway and Transportation District, an entity that oversees the bridge itself and the buses and ferries that operate in the area. Most of its revenues' come from tolls and fares, and the district loses money. A barrier would cost between $15 million and $ 25 million. So the Psychiatric Foundation of Northern California, which has adopted the barrier as its cause, considers it a success that the board has merely allowed a feasibility study, for which various private and public donors have raised$ 2 million. Mel Blaustein, a director at the foundation, has heard several arguments against a barrier over the years-too ugly, too expensive, and so forth--but the most persistent has been that people would simply kill themselves somewhere else, so why bother.'? This is nonsense, he says, "Most suicides are impulsive and preventable." A bridge without a barrier, adds Pat Hines, Kevin's father, is "like leaving a loaded gun in the psychiatric ward."

单选题The author calls the wealth of the richest "paper fortunes" because

单选题The passage explicitly answers the question