单选题A rope 60 meters long is cut into three pieces A, B, C, If piece A is 12 meters longer than piece B, piece B is 9 meters shorter than piece C, then what is the length, in meters, of the shortest piece

单选题25. Economist: Any country that is economically efficient will generate wealth. Such a country will remain politically stable only if that wealth is distributed equitably. The equitable distribution of wealth puts an end to risk taking, the indispensable precondition of economic efficiency. Which of the following conclusions can be properly drawn at the basis of the statements above? ______

单选题 Under controlled conditions

单选题. ①Projecting the idea of a distinctive female demand in seventeenth- and eighteenth-century England was a groundbreaking departure in the history of marketing. ②The pioneers were the booksellers and printers who addressed specialist titles to the ladies in the 1600s, while the post-1688 print boom saw the publication of custom-designed ladies' pocket diaries, a proliferation of female manuals of all kinds, the Female Spectator in the 1740s and the long-running Lady's Magazine from 1770. ③The leap to objects was made when leading furniture makers started classifying furniture by the sex, age, and specialist needs of the implied user in the new illustrated catalogs of the 1760s. ④Of course, sex distinctions in clothes are as old as civilization, while the idea of furniture suited to female needs is not unprecedented (think of birthing stools), but making difference systematic and concrete by means of word, image, and object was a decisive innovation. ⑤The rapid diffusion of ladies' and gentlemen's furniture suggests that gender distinctions already resonated powerfully with male and female consumers, but in the extension of the range of differentiated furniture, the projection of the trope by manufacturers thereafter, and its acceptance by consumers, conventional ideas of masculine importance and feminine delicacy were amplified and fixed. ⑥In the process, femininity was expressed in a specific and narrowly defined aesthetic register.3. According to the passage, which of the following is true about furniture prior to the 1760s? ______

单选题. This passage is adapted from material published in 2002. ①In 1971, hot on the heels of plate-tectonic theory's acceptance, J. W. Morgan suggested that hotspots—areas of intense volcanism such as Hawaii, Yellowstone, and Iceland—are fueled by plumes of hot material arising in the deep mantle and punching through the mobile shallow mantle and crust to the surface. ②Morgan's theory was developed to explain the time-progressive trails of volcanoes associated with some hotspots and the hotspots' apparent fixity relative to one another. ③If the sources of the volcanism were rooted in the immobile deep mantle, they would not move relative to one another and the plates at the surface would drift above, bearing away trails of volcanism. ④According to a recent article by geologist G. R. Foulger, however, although hotspots do exist, they do not have time-progressive volcanic trails and are not fixed relative to one another.7. The passage implies that Morgan's suggestion was ______

单选题xy=35Quantity A: xQuantity B: y

单选题某个人在买价值500元书的时候，先首期付了100元，剩下的带利息的余款采用如下方式支付：连续30个月每月支付15元，最后再付10元，问最后所付利息是借款的百分之几?

单选题. ①Ecologists had assumed that trees in the consistently warm tropics grew at a slow but steady rate, unvarying from year to year. ②However, a study at La Selva, Costa Rica, showed that trees grew less in hotter years and more in cooler ones: between 1984 and 2000, dramatic differences occurred in the six species of trees studied, with trees adding twice as much wood in some cooler years as they did in the scorching El Nino year of 1997-1998. ③Because tree growth is an index of the balance between photosynthesis, in which trees absorb carbon dioxide (CO2) from the atmosphere and release oxygen, and respiration, in which the opposite occurs, the La Selva data were the first hint that rapidly rising global temperatures, driven by human-generated emissions of CO2, may be pushing tropical forests to release more CO2, thereby intensifying global warming. ④This raised serious questions about a popular theory that tropical forests act as a sponge, soaking up much of the excess CO2 that humans pump into the atmosphere. ⑤The La Selva data are consistent with a model of global CO2 flux developed by Keeling, who concluded that the amount of CO2 taken up in tropical landmasses rose in cooler years and fell in hotter ones, accounting for year-to-year changes in the amount of CO2 that stays in the atmosphere.29. The primary purpose of the passage is to ______

单选题38. According to ancient records, the first sales tax that the government of Selea imposed was a tax of two centima coins on every jar of cooking oil sold in Selea. Tax records show that despite a stable population, revenues from the oil tax declined steeply over the first two years that the tax was in effect. Therefore, a significant proportion of Seleans must have failed to pay taxes on the cooking oil they purchased. Which of the following, if true, most seriously weakens the argument given?

单选题 ①In The Life of Charlotte Bronte(1857)

单选题6个相同的球放在1，2，3，4四个杯中，要求每个杯中至少放一个，一共有多少种不同的放法?

单选题三条直线能够把一个圆的内部最多分成多少个没有重叠部分的区域?

单选题. ①Astronomers studying a certain kind of supernova (exploding star) were surprised to find the supernovas were fainter than expected. ②Seeking explanations, they discounted the possibility that cosmic dust might be screening out some of the light, because it would filter out blue light more than red, causing the supernovas to appear redder than they really are. ③Also, unless spread very smoothly throughout space, the dust would introduce large variations in the measurements. ④Another possibility is gravitational lensing, the bending of light rays as they skirt galaxies en route. ⑤Such lensing occasionally causes brightening, but most often it contributes to the dimness of distant supernovas. ⑥Calculations show, however, that this effect becomes important only for sources more distant than the supernovas studied.45. According to the passage, the astronomers rejected gravitational lensing as an explanation for their findings because ______

单选题. ①One might assume the most admired architecture would be the best built. ②This was generally true in the past, but in the twentieth century, when new materials and new aesthetic theories often drove architects to cavalier experimentation, even celebrated architects fell short. ③When designing the Centre Georges Pompidou in Paris, Renzo Piano and Richard Rogers turned the building literally inside out. ④.Previously hidden elements such as pipes, ducts, and elevators were exposed to view—and exposed to the elements. ⑤The result might have been foreseen: after only twenty years, the building was closed for a two-year renovation. ⑥Although the authorities maintained that the unexpectedly large numbers of visitors necessitated the renovation, much of the budget was spent on refurnishing the facade.17. Which of the following best describes the function of the highlighted sentence? ______

单选题17. A decrease in face-to-face social contact can precipitate depression. Time spent using the Internet cannot be spent in face-to-face social contact, so psychologists have speculated that sharply increasing Internet use can cause depression. Studies of regular Internet users have found a significantly higher incidence of depression among those who had recently doubled the amount of time they spent using the Internet than among those whose use had not increased. Hence, the psychologists' speculation is correct. Which of the following is an assumption on which the argument depends? ______

单选题 Historian: In the Drindian Empire

单选题the unit’s digit of 7n is x and the unit’s digit of 3n is y where n is a positive integerQuantity A: |x-y|Quantity B: 3

单选题. ①The waters east of Cape Hangklip were once the center of a lucrative wild-caught abalone fishery, but illegal fishing in the mid-1990s escalated to such levels that the recreational fishery was closed in 2003. ②When abalones did not rebound, commercial fishing was also banned. ③Continue declines in abalone were attributed to poaching, but an invasion by rock lobsters during the early 1990s probably intensified the trend. ④Rock lobsters prey on sea urchins, and increased rock lobster densities coincided with significant decreases in urchins. ⑤In that area, urchins feed largely by trapping drift kelp, and in doing so provide juvenile abalone with both protective shelter and nourishment. ⑥Without urchins' presence, juvenile abalones are less likely to survive to adulthood.35. According to the passage, since the early 1990s, sea urchins in the waters east of Cape Hangklip have ______

单选题 For the first time

单选题. ①Most mammals reach sexual maturity when their growth rates are in decline, whereas humans experience a growth spurt during adolescence. ②Whether apes experience an adolescent growth spurt is still undecided. ③In the 1950s, data on captive chimpanzees collected by James Gavan appeared devoid of evidence of an adolescent growth spurt in these apes. ④In a recent reanalysis of Gavan's data, however, zoologist Elizabeth Watts has found that as chimpanzees reach sexual maturity, the growth rate of their limbs accelerates. ⑤Most biologists, however, are skeptical that this is a humanlike adolescent growth spurt. ⑥While the human adolescent growth spurt is physically obvious and affects virtually the entire body, the chimpanzee's increased growth rate is detectable only through sophisticated mathematical analysis. ⑦Moreover, according to scientist Holly Smith, the growth rate increase in chimpanzees begins when 86% of full skeletal growth has been attained, whereas human adolescence generally commences when 77 percent of full skeletal growth has occurred.26. Which of the following best describes the main idea of the passage? ______