单选题. ①Octopuses show surprising cognitive abilities: solving mazes, learning cues, and remembering solutions. ②Furthermore, recent studies suggest that octopuses may display the first "personalities" ever measured in an invertebrate: confronted with the same threats and food stimuli, individual octopuses react differently. ③Until recently, such traits were thought to be exclusive to higher vertebrates and to develop primarily among long-lived, social animals. ④Longevity, it was thought, justifies the biological "investment" in big, complex brains. ⑤Why would the short- lived, solitary octopus develop such traits? ⑥Mather postulates that animals that pursue varied food sources in changeable, perilous habitats must develop a wide range of hunting and defensive strategies. ⑦Variation in the temperament of individuals enhances survival in a volatile, competitive milieu by ensuring that different individuals respond differently to changing conditions so some will thrive.1. Which of the following best describes the function of the highlighted sentence? ______

单选题If x is an even integer, which of the following is an odd integer?

单选题Quantity A: The Standard Deviation of 1, 3, 5,7,9, 11, 13, 15, 17, 19Quantity B: The Standard Deviation of 2, 4, 6, 8, 10, 12, 14, 16, 18, 20

单选题the remainder whenQuantity A: 2×10100+1 is divided by 3Quantity B: 1

单选题4. In 1998 the United States Department of Transportation received nearly 10,000 consumer complaints about airlines; in 1999 it received over 20,000. Moreover, the number of complaints per 100,000 passengers also more than doubled. In both years the vast majority of complaints concerned flight delays, cancellations, mishandled baggage, and customer service. Clearly, therefore, despite the United States airline industry's serious efforts to improve performance in these areas, passenger dissatisfaction with airline service increased significantly in 1999. Which of the following, if true, most seriously weakens the argument? ______

单选题. ①One way to determine which planets outside the solar system might harbor life is to look for telltale signs in their light. ②Living organisms create a chemical disequilibrium in their environment, typically indicated by a molecule whose presence can be explained only if some presence is continually regenerating it. ③For example, Earth's atmosphere contains oxygen because photosynthesis produces it faster than it is lost through processes such as the rusting of iron in rocks. ④However, chemical disequilibrium does not necessarily indicate the presence of life because, as in the case of methane on Mars, the imbalance could arise through nonbiological processes.41. The passage mentions that "Earth's atmosphere contains oxygen" primarily in order to ______

单选题 Although initially symptomless

单选题 ①What accounts for the low-lying

单选题Quantity A: n is an integer less than 1 the standard deviation of 1, 2, nQuantity B: the standard deviation of 1, 2, 1

单选题On a road there is a tree every 46 meters. If the trees are numbered consecutively, what is the number of the tree 5060 meters past tree number 56?

单选题. ①Seeding a forest with nonnative species after a fire can impede native plant regeneration and spread invasive species in vulnerable fire-affected soils. ②Moreover, native seed sources are almost always sufficient for early nature reestablishment of native species, so planting should be considered only when natural regeneration is unlikely. ③Replanting dense stands of fast-growing conifers—a common postfire management practice—truncates the biologically rich early stage of ecological succession and can increase the severity of future fires. ④Other treatments should be carefully scrutinized for their potential to spread noxious weeds. ⑤For instance, straw much applied extensively to reduce erosion after the 2002 Hayman Fire in Colorado was contaminated with cheatgrass, an invasive grass difficult to control or eradicate once established.9. According to the passage, which of the following is a consequence of replanting an area with dense stands of fast-growing conifers after a fire? ______

单选题.①Madagascar's Mahafale cattle raisers have incorporated the prickly pear cactus into their pastoral economy, which depends on assisting their cattle through the dry season, when grass and water are scarce. ②Rather than relying on nomadism in the pursuit of water and pasture for their livestock, they have turned to cactus to keep stock alive. ③This has influenced the cattle raisers' way of life, particularly in terms of diet and mobility. ④Women harvest cactus for their families to eat. ⑤Male herders work cactus as a vegetable crop for cattle. ⑥For these benefits, pastoralists sow, prune, and shape prickly pear into living fences around their corrals. ⑦In doing so, these herders have become cactus cultivators, which has reduced their mobility.41. Select the sentence in the passage that tells how the prickly pear has affected the Mahafale diet.

单选题6. Recently an unusually high number of dolphins have been found dead of infectious diseases, and most of these had abnormally high tissue concentrations of certain compounds that, even in low concentrations, reduce dolphins' resistance to infection. The only source of these compounds in the dolphins' environment is boat paint. Therefore, since dolphins rid their bodies of the compounds rapidly once exposure ceases, their mortality rate should decline rapidly if such boat paints are banned. Which of the following, if true, most strengthens the argument? ______

单选题Quantity A: the standard deviation of 10, 45, 50, 55, 90Quantity B: the standard deviation of 10, 30, 50, 70, 90

单选题两个质数的和是40，求这两个质数的乘积的最大值是多少?

单选题Two dices each has six sides, which represent six values 1, 2, 3, 4, 5, 6 respectively. Cast the two dices and get two values, what is the probability of one value being 2 more than the other?

单选题In the figure above, the area of the circular region with center O is 16π, if AB=AC, what is the length of AB?