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Set 1NORTH AMERICAN GRASSLANDS1.In North America, native grasslands occur primarily in the Great Plains in the middle of the continent. The North American prairie biome is one of the most extensive grasslands in the world, extending from the edge of the Rocky Mountains in the west to the deciduous forest in the east, and from northern Mexico in the south to Canada in the north. Average annual rainfall ranges from about 40 cm (16 inches) in the west to 80 cm (31 inches) in the east. Average annual temperatures range between 10 degrees and 20 degrees Celsius (50 to 68 degrees Fahrenheit). In the moist regions of the North American grasslands, especially in the northern Great Plains, rainfall is distinctly seasonal, and temperatures can vary widely from very hot in summer to bitter cold in winter.2.One hundred years ago, the Great Plains grasslands were one vast, unbroken prairie. Much of the prairie is now farmland, the most productive agricultural region in the world, dominated by monocultures of cereal grains. Wheat, barley, soybeans, corn, and sunflowers occupy the land that was once prairie. In areas given over to grazing lands for cattle and sheep, virtually all the major native grasses have been replaced by alien species.3.An important feature of the northern Great Plains grasslands is the presence of millions of glacial depressions that are now small ponds known as prairie potholes. They were formed during the most recent Ice Age, when streams flowed in tunnels beneath glacially formed sandy ridges. When the Ice Age ended around 12,000 years ago, the retreating glaciers created about 25 million depressions across a 300,000-square-mile landscape—about 83 potholes per square mile. As the ice blocks melted, much of the water was left behind, forming wetlands ranging in size from a tenth of an acre to several acres. The wetlands were soon surrounded by fluttering waves of grasses: shortgrass, mixed grass, and tallgrass.4.Today these small wetlands still cover the prairies, although much of the landscape— including both native grasses and potholes—has been transformed to cropland and grassland for grazing. What does remain of the wetlands, however, still serves as an important breeding area for more than 300 bird species, including large numbers of migrating shorebirds and waterfowl. The potholes fill up with water during spring rains and usually dry out by late summer. Every spring, birds arrive in great numbers—northern pintails, mallards, coots, and pied-billed grebes—4 to 6 million strong, to mate in the seasonal wetlands that dot portions of Minnesota, Iowa, North and South Dakota, Montana, Alberta, Saskatchewan, and Manitoba. Prairie pothole country produces half of North America’s 35 to 40 million ducks and is renowned worldwide as a "duck factory."5.Recently biologists have discovered that the prairie pothole region is potentially a vast carbon sink: a natural sponge that absorbs carbon dioxide emissions from cars, factories, and power plants. Carbon dioxide is the most common of all the pollutants acting as greenhouse gases that heat up the atmosphere. Fortunately, however, carbon dioxide is captured naturally and stored in trees, soil, and plants. Scientists have termed this "carbon sequestration." They have determined that prairie potholes hold an average of 2.5 tons of carbon per acre per year when not being farmed. This means that if the entire pothole region in the United States and Canada were to stop being farmed, the region would store about 400 million tons of carbon over 10 years—the equivalent of taking almost 4 million cars off the road. Thus, preserving the potholes could be a way to offset greenhouse gas emissions that are warming the planet.Glossary:biome: one of the world’s major natural communities, classified by predominant vegetationmonoculture: cultivation of large land areas with a single plant variety The word offset in paragraph 5 is closest in meaning to （）.
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Set 4THE TRICKSTER FIGURE IN MYTHOLOGY1.In the study of mythology, the character known as the trickster is a god, spirit, human, or animal who breaks the rules of the gods or nature, sometimes maliciously but usually with results that are positive. The rule breaking often takes the form of mischief or thievery. The trickster is usually male but occasionally disguises himself in female form. He can be cunning or foolish, or both, and often very humorous. His curiosity leads him into trouble, but he rescues himself with his sly wit. When he plays tricks, he performs important cultural tasks that benefit humans, and for this reason the trickster is a significant figure in world mythology.2.In different cultures, the trickster and the hero are combined in various ways. In Greek mythology, Prometheus steals fire from the gods and gives it to humans, a feat making him more of a hero than a trickster, and he is usually portrayed as an intellectual. In many Native American stories, Coyote also steals fire from the gods, but Coyote is usually more of a jokester or a prankster than an intellectual.3.The trickster is both creator and destroyer, giver and taker, one who tricks others and is tricked in return. The pranks of the trickster are compulsive and uncontrollable. He does not act consciously; he acts out of passion and impulse. He knows neither good nor evil, yet he is responsible for both. He possesses no morals, yet through his behavior morality comes into being. According to psychologist Carl Jung, the trickster is "a primitive cosmic being of divine-animal nature, on the one hand superior to man because of his superhuman qualities, and on the other hand inferior to him because of his unreason and unconsciousness."4.In Native American mythology, the majority of trickster myths concern the creation or transformation of the earth. Such stories have a trickster who is always wandering, who is always hungry, who is not guided by normal ideas of good and evil, and who possesses some magical powers. In some stories he is a deity, and in others he is an animal or human subject to death. Several of these myths feature Raven or Coyote as the trickster-hero.5.In many creation myths of the Pacific Northwest, Raven illustrates the transformational nature of tricksters. Raven is the greatest shapeshifter of all and can change into anything to get what he wants. In one story, there is darkness at the beginning of the world, so Raven decides he will find light. He flies far from the earth, searching in the darkness, until he spots a glimmer of light coming from a window in the house of the gods. Raven knows the gods are protective of their possessions, so he devises a trick. He perches on a pine branch next to the house and watches each day as the chief god’s daughter draws water from a nearby lake. He magically transforms himself into a pinyon seed and falls into the girl’s drinking cup. The girl swallows the seed, which grows within her body, and she eventually gives birth to a boy. The child delights his grandparents, and his laughter tricks the elder gods into revealing where they hide a shining ball of light. The gods give the child the ball to play with, and then Raven transforms back to a bird and flies off carrying the ball of light in his beak. He hangs the ball-the sun-in the sky, bringing light to the world.6.Coyote’s character is similar to that of Raven’s, and both appear in stories carrying out similar roles. In several stories from the American Southwest, Coyote steals fire from a group of "fire beings" and gives it to humans. In some tales Coyote wants to make human life more interesting, so he introduces sickness, sorrow, and death. He often teaches through negative example by employing the human vices of lying, cheating, and stealing. His tricks often bring about destructive natural phenomena, such as a great flood that destroys the earth. However, by causing the flood, Coyote leads the human race to a new and better world. Coyote shows us that at the heart of the trickster is a savior whose great gift to humans is showing them new ways of knowing and doing.Glossary:mischief: tendency to play tricks or cause minor troublemischief: the act of theft; stealingpinyon seed: the seed of a pine tree; pine nut The word savior in paragraph 6 is closest in meaning to （）.
Set 5THE DOMESTICATION OF ANIMALS1.The domestication of wild species led directly to denser human populations by yielding more food than the hunter-gatherer lifestyle could provide. In societies that possessed domestic animals, livestock helped to feed more people by providing meat, milk, and fertilizer, and by pulling plows. Large domestic animals became the societies’ main source of animal protein, replacing wild game, and they also furnished wool, leather, and land transport. Humans have domesticated only a few species of large animals, with "large" defined as those weighing over 100 pounds (45 kilograms). Fourteen such species were domesticated before the twentieth century, all of them terrestrial mammals and herbivores. The five most important of these are sheep, goats, pigs, horses, and cattle or oxen.2.Small animals such as ducks, geese, rabbits, dogs, cats, mink, bees, and silkworms have also been domesticated. Many of these small animals provided food, clothing, or warmth. However, none of them pulled plows or wagons, none carried riders, and none except dogs pulled sleds. Furthermore, no small domestic animals have been as important for food as have large domestic animals.3.Early herding societies quickly domesticated all large mammal species that were suitable for domestication. There is archaeological evidence that these species were domesticated between 10,000 and 4,500 years ago, within the first few thousand years of the origins of farming-herding societies after the last Ice Age. The continent of Eurasia has been the primary site of large mammal domestication. Having the most species of wild mammals to begin with, and losing the fewest to extinction in the last 40,000 years, Eurasia has generated the most candidates for domestication.4.Domestication involves transforming wild animals into something more useful to humans. Truly domesticated animals differ in many ways from their wild ancestors. These differences result from two processes: human selection of individual animals that are more useful to humans than other individuals of the same species, and evolutionary responses of animals to the forces of natural selection operating in human environments rather than in wild environments.5.To be domesticated, a wild species must possess several characteristics. A candidate for domestication must be primarily a herbivore because it takes less plant biomass to feed a plant eater than it does to feed a carnivore that consumes plant eaters. No carnivorous mammal has ever been domesticated for food simply because it would be too costly. A candidate must not only weigh an average of over 100 pounds but also grow quickly. That eliminates gorillas and elephants, even though they are herbivores. Moreover, candidates for domestication must be able to breed successfully in captivity.6.Since almost any sufficiently large mammal species is capable of killing a human, certain qualities disqualify a wild animal for domestication. The animal cannot have a disposition that is nasty, dangerous, or unpredictable—characteristics that eliminate bears, African buffaloes, and some species of wild horses. The animal cannot be so nervous that it panics around humans. Large herbivorous mammal species react to danger from predators or humans in different ways. Some species are nervous, fast, and programmed for instant flight when they perceive danger. Others are less nervous, seek protection in herds, and do not run until necessary. Most species of deer and antelope are of the former type, while sheep and goats are of the latter.7.Almost all domesticated large mammals are species whose wild ancestors share three social characteristics: living in a herd, maintaining a dominance hierarchy in the herd, and having herds that occupy overlapping home ranges instead of mutually exclusive territories. Humans have taken advantage of these characteristics in keeping domestic animals together with others of their species and in close proximity to other species of domestic animals.Glossary:terrestrial: living on land rather than in waterherbivores: animals that feed mainly on plants All of the following are characteristics favorable to domestication EXCEPT （）.
Set 5THE DOMESTICATION OF ANIMALS1.The domestication of wild species led directly to denser human populations by yielding more food than the hunter-gatherer lifestyle could provide. In societies that possessed domestic animals, livestock helped to feed more people by providing meat, milk, and fertilizer, and by pulling plows. Large domestic animals became the societies’ main source of animal protein, replacing wild game, and they also furnished wool, leather, and land transport. Humans have domesticated only a few species of large animals, with "large" defined as those weighing over 100 pounds (45 kilograms). Fourteen such species were domesticated before the twentieth century, all of them terrestrial mammals and herbivores. The five most important of these are sheep, goats, pigs, horses, and cattle or oxen.2.Small animals such as ducks, geese, rabbits, dogs, cats, mink, bees, and silkworms have also been domesticated. Many of these small animals provided food, clothing, or warmth. However, none of them pulled plows or wagons, none carried riders, and none except dogs pulled sleds. Furthermore, no small domestic animals have been as important for food as have large domestic animals.3.Early herding societies quickly domesticated all large mammal species that were suitable for domestication. There is archaeological evidence that these species were domesticated between 10,000 and 4,500 years ago, within the first few thousand years of the origins of farming-herding societies after the last Ice Age. The continent of Eurasia has been the primary site of large mammal domestication. Having the most species of wild mammals to begin with, and losing the fewest to extinction in the last 40,000 years, Eurasia has generated the most candidates for domestication.4.Domestication involves transforming wild animals into something more useful to humans. Truly domesticated animals differ in many ways from their wild ancestors. These differences result from two processes: human selection of individual animals that are more useful to humans than other individuals of the same species, and evolutionary responses of animals to the forces of natural selection operating in human environments rather than in wild environments.5.To be domesticated, a wild species must possess several characteristics. A candidate for domestication must be primarily a herbivore because it takes less plant biomass to feed a plant eater than it does to feed a carnivore that consumes plant eaters. No carnivorous mammal has ever been domesticated for food simply because it would be too costly. A candidate must not only weigh an average of over 100 pounds but also grow quickly. That eliminates gorillas and elephants, even though they are herbivores. Moreover, candidates for domestication must be able to breed successfully in captivity.6.Since almost any sufficiently large mammal species is capable of killing a human, certain qualities disqualify a wild animal for domestication. The animal cannot have a disposition that is nasty, dangerous, or unpredictable—characteristics that eliminate bears, African buffaloes, and some species of wild horses. The animal cannot be so nervous that it panics around humans. Large herbivorous mammal species react to danger from predators or humans in different ways. Some species are nervous, fast, and programmed for instant flight when they perceive danger. Others are less nervous, seek protection in herds, and do not run until necessary. Most species of deer and antelope are of the former type, while sheep and goats are of the latter.7.Almost all domesticated large mammals are species whose wild ancestors share three social characteristics: living in a herd, maintaining a dominance hierarchy in the herd, and having herds that occupy overlapping home ranges instead of mutually exclusive territories. Humans have taken advantage of these characteristics in keeping domestic animals together with others of their species and in close proximity to other species of domestic animals.Glossary:terrestrial: living on land rather than in waterherbivores: animals that feed mainly on plants What can be inferred from paragraph 6 about deer and antelope ？（）
Set 4THE TRICKSTER FIGURE IN MYTHOLOGY1.In the study of mythology, the character known as the trickster is a god, spirit, human, or animal who breaks the rules of the gods or nature, sometimes maliciously but usually with results that are positive. The rule breaking often takes the form of mischief or thievery. The trickster is usually male but occasionally disguises himself in female form. He can be cunning or foolish, or both, and often very humorous. His curiosity leads him into trouble, but he rescues himself with his sly wit. When he plays tricks, he performs important cultural tasks that benefit humans, and for this reason the trickster is a significant figure in world mythology.2.In different cultures, the trickster and the hero are combined in various ways. In Greek mythology, Prometheus steals fire from the gods and gives it to humans, a feat making him more of a hero than a trickster, and he is usually portrayed as an intellectual. In many Native American stories, Coyote also steals fire from the gods, but Coyote is usually more of a jokester or a prankster than an intellectual.3.The trickster is both creator and destroyer, giver and taker, one who tricks others and is tricked in return. The pranks of the trickster are compulsive and uncontrollable. He does not act consciously; he acts out of passion and impulse. He knows neither good nor evil, yet he is responsible for both. He possesses no morals, yet through his behavior morality comes into being. According to psychologist Carl Jung, the trickster is "a primitive cosmic being of divine-animal nature, on the one hand superior to man because of his superhuman qualities, and on the other hand inferior to him because of his unreason and unconsciousness."4.In Native American mythology, the majority of trickster myths concern the creation or transformation of the earth. Such stories have a trickster who is always wandering, who is always hungry, who is not guided by normal ideas of good and evil, and who possesses some magical powers. In some stories he is a deity, and in others he is an animal or human subject to death. Several of these myths feature Raven or Coyote as the trickster-hero.5.In many creation myths of the Pacific Northwest, Raven illustrates the transformational nature of tricksters. Raven is the greatest shapeshifter of all and can change into anything to get what he wants. In one story, there is darkness at the beginning of the world, so Raven decides he will find light. He flies far from the earth, searching in the darkness, until he spots a glimmer of light coming from a window in the house of the gods. Raven knows the gods are protective of their possessions, so he devises a trick. He perches on a pine branch next to the house and watches each day as the chief god’s daughter draws water from a nearby lake. He magically transforms himself into a pinyon seed and falls into the girl’s drinking cup. The girl swallows the seed, which grows within her body, and she eventually gives birth to a boy. The child delights his grandparents, and his laughter tricks the elder gods into revealing where they hide a shining ball of light. The gods give the child the ball to play with, and then Raven transforms back to a bird and flies off carrying the ball of light in his beak. He hangs the ball-the sun-in the sky, bringing light to the world.6.Coyote’s character is similar to that of Raven’s, and both appear in stories carrying out similar roles. In several stories from the American Southwest, Coyote steals fire from a group of "fire beings" and gives it to humans. In some tales Coyote wants to make human life more interesting, so he introduces sickness, sorrow, and death. He often teaches through negative example by employing the human vices of lying, cheating, and stealing. His tricks often bring about destructive natural phenomena, such as a great flood that destroys the earth. However, by causing the flood, Coyote leads the human race to a new and better world. Coyote shows us that at the heart of the trickster is a savior whose great gift to humans is showing them new ways of knowing and doing.Glossary:mischief: tendency to play tricks or cause minor troublemischief: the act of theft; stealingpinyon seed: the seed of a pine tree; pine nut It can be inferred from the passage that the author most likely believes which statement about the trickster ？（）
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