单选题 ①Pikas are small

单选题 Homeowners often weatherize their homes, that is

单选题. ①One reason researchers have long believed that Mars never enjoyed an extensive period of warm and wet climate is that much of the surface not covered by wind-borne dust appear to be composed of unweathered material. ②If water flowed for an extended period, researchers reasoned, it should have altered and weathered the volcanic minerals, creating clays or other oxidized, hydrated phases (minerals that incorporate water molecules in their crystal structure). ①It turns out, though, that the scientists were not looking closely enough. ②New high-resolution mapping data and close-up surface studies have revealed clays and other hydrated minerals in many regions. ③The clay deposits are scattered all over, in ancient volcanic surfaces and heavily cratered highland regions, some of which have apparently been exposed by erosion only recently.37. According to the passage, scientists are able to discover weathered material on the Martian surface because they have benefited from which of the following? ______

单选题If x is an integer, then the least possible value of | 128-5x | is

单选题x=1000yQuantity A: the sum of digits of xQuantity B: the sum of digits of y

单选题100个人中，88个有电视，76个有报纸，有电视没报纸的是x个，问有报纸没电视的有多少?

单选题There are 24 positive integers in a sequence, the first 12 integers are less than 50 and the second 12 integers are greater than 50.Quantity A: the median of the sequenceQuantity B: 50

单选题a+b2=a2+b2, and a=1Quantity A: aQuantity B: b

单选题. ①Data of modern and historic peasant communities suggest that individuals and communities specialize in ceramic production for trade primarily to offset subsistence shortfalls arising from inadequate or insufficient agricultural land. ②Harry investigated whether this correlation of ceramic specialization with agricultural marginality occurred among prehistoric inhabitants of the American Southwest. ③At Arizona's West Branch site, occupied A. D. 900-1100, abundant pottery manufacturing materials suggest village-wide ceramic production in excess of that needed for household purposes.3. The final sentence of the passage primarily serves to do which of following? ______

单选题. ①Constant variations in the amount of sunlight available on Earth at any given location make energy storage a necessary design feature of terrestrial solar-energy systems. ②For systems transforming solar to thermal energy, the thermal energy may be stored in matter as either latent heat or sensible heat. ③Latent heat is absorbed or released whenever matter changes phase, as when matter changes from liquid to gas, for example, or from gas to liquid. ④Large heat capacities are associated with certain materials, like salts, but in any substance this storage is available only at the unique fixed temperature at which the particular phase transition occurs in that substance. ⑤Moreover, materials that have transitions at the temperatures that terrestrial solar-energy systems are likely to encounter are usually destructively corrosive at those temperatures. ⑥The storage of sensible heat, on the other hand, allows flexibility as to temperature, in addition, safe substances like water and most rocks have large sensible heat capacities.6. The primary purpose of the passage is to discuss which of the following? ______

单选题 To save the Amazon rain forest from destruction

单选题. ①Buell's study of village sketches (a type of fiction popular in the United States in the 1830s and 1840s) provides a valuable summary of sketches that portray the community as homogeneous and fixed, but it ignores those by women writers, which typically depicted the diversity that increasingly characterized actual village communities at that time. ②These women's geographical mobility was restricted (although women writers of the time were not uniformly circumscribed in this way), and their subject matter reflected this fact. ③Yet their texts were enriched by what Gilligan, writing in a different context, has called the ability to attend to voices other than one's own. ④To varying degrees, the women's sketches portray differences among community members: all stress differences among men and among women (particularly the latter) as well as differences between the sexes, and some also depict cultural diversity. ⑤These writers represent community as dynamic, as something that must be negotiated and renegotiated because of its members' divergent histories, positions, expectations, and beliefs.13. According to the passage, village sketches written by women in the United States in the 1830s and 1840s typically reflected ______

单选题3x2=23k25k represents a single digitQuantity A: kQuantity B: 1

单选题. ①Meltzoff and Moore reported experiments showing that human newborns possess the ability to imitate certain facial expressions, such as a protruding tongue or an open mouth. ②Yet numerous researchers challenge Meltzoff's interpretation that such neonatal imitation is the origin of later imitation, which appears at approximately eight to twelve months of age. ③These researchers point out that the neonatal imitative response disappears or is lessened at approximately two months. ④Moreover, since in follow-up studies only one type of imitative response toward a facial expression (that is, tongue protrusion) was observed, some researchers assert that neonatal imitation is not imitation at all but may simply be a form of exploratory behavior in response to interesting stimuli.9. According to the passage, those who challenge "Meltzoff's interpretation" do so on the basis that it ______

单选题1. The Minoan civilization flourished on the island of Crete around 2000 B.C. The discovery on Crete of large numbers of bronze implements and the furnaces used in their manufacture shows that the Minoans had a thriving bronze industry. Moreover, many bronze artifacts from this period that are similar in style to those produced on Crete have been found in southern Greece. Hence it is probable that, besides making bronzeware for domestic use, the Minoans exported bronzeware to southern Greece. Which of the following, if true, most strengthens the argument given? ______

单选题xy＜0Quantity A: |x+y|Quantity B: |x|+|y|

单选题. ①Scientific consensus is that humans first began to have a warming effect on Earth's climate within the past century, after coal-burning factories, power plants, and motor vehicles began releasing carbon dioxide (CO2) and other greenhouse gases in significant quantities into the air. ②However, evidence suggests that human agricultural activities may have had such an effect much earlier: concentrations of CO2 started rising about 8000 years ago, even though natural trends indicate they should have been dropping; methane levels rose similarly about 3,000 years later. ③Without these rises, however, current temperatures in northern parts of North America and Europe would be cooler by three to four degrees Celsius—enough to inhibit agriculture—and an ice age would probably have begun several thousand years ago in northeastern Canada.45. Which of the following best describes the function of the highlighted sentence? ______

单选题 In a certain country

单选题. ① In 1755 British writer Samuel Johnson published an acerbic letter to Lord Chesterfield rebuking his patron for neglect and declining further support. ②Johnson's rejection of his patron's belated assistance has often been identified as a key moment in the history of publishing, marking the end of the culture of patronage. ③However, patronage had been in decline for 50 years, yet would survive, in attenuated form, for another 50. ④Indeed, Johnson was in 1762 awarded a pension by the Crown—a subtle form of sponsorship, tantamount to state patronage. ⑤The importance of Johnson's letter is not so much historical as emotional; it would become a touchstone for all who repudiated patrons and for all who embraced the laws of the marketplace.37. The author of the passage mentions Johnson's 1762 pension award in order to ______

单选题. ①Recent studies of the Philippine fruit bat fauna have confirmed some previous hypotheses regarding bats on oceanic islands: for example, species richness [the number of different species in a particular area] and abundance are generally highest in the lowlands and decrease with increasing elevation. ②With few exceptions, each endemic species [species native to a particular place] is restricted to the modern islands that made up a single island during periods of low sea level, and genetic differentiation has been influenced by the ecology of the species and the current and past geographic and geological conditions. ③However, far more previous hypotheses have been overturned than supported. ④Some endemic Philippine species use disturbed habitat as extensively as nonendemic species that are widespread in Southeast Asia. ⑤Levels of genetic variation within all species are high, not low, and rather than showing evidence of an intrinsic vulnerability to extinction from natural causes, independent lineages of these bats have persisted in rather small areas for very long periods of time (often millions of years) in spite of frequent typhoons and volcanic eruptions. ⑥While colonization from outside areas has clearly contributed to the high species richness, speciation within the archipelago has contributed at least a quarter of the total species richness, including many of the most abundant species.13. The primary purpose of the passage is to ______