WhydoesthestudentwanttoauditthecourseA．S
Why does the student want to audit the course
A、She needs the additional credits.
B．It is a prerequisite for another class.
C．She does not want to pay tuition.
D．She needs to learn the material.{$mediaurl}WhydoestheprofessormentionRur
{$mediaurl} Why does the professor mention Rural FreeDelivery and Parcel Post
A．To give examples of early mail-order houses
B．To compare the benefits of two different types of services
C．To explain how these services helped the mail-order business
D．To describe the origins of the concept of customer service1Mostmatterexistsascompounds---combinati
1 Most matter exists as compounds---combinations of atoms or oppositely charged ions of two or more different elements held together in fixed proportions by chemical bonds.Compounds are classified as organic or inorganiC、Organic compounds contain atoms of the element carbon, usually combined with itself and with atoms of one or more other elements such as hydrogen, oxygen, nitrogen, sulfur, phosphorus, and chlorine. Many materials important to us--food, vitamins, blood, skin, cotton, wool, paper, oil, plastics--are organic compounds.
2 Larger and more complex organic compounds, called polymers, consist of a number of basic structural units linked together by chemical bonds. Important organic polymers include carbohydrates, proteins, and nucleic acids.Carbohydrates, such as the complex starches in rice and potato plants, are composed of a number of simple sugar molecules. Proteins are produced in plant and animal cells by the linking of different numbers and sequences of about twenty different structural units known as amino acids. Most animals, including humans, can manufacture about ten of these amino acids in their cells, but the other ten, called essential amino acids, must be obtained from food in order to prevent protein deficiency. Nucleic acids are composed of hundreds to thousands of four different units called nucleotides linked together in different numbers and sequences.DNA、and RNA、in plant and animal cells are nucleic acids.
Which of the following statements applies to all organic compoundsA．They are composed of carbon and one or more other elements.
B．They contain atoms of the seven most abundant elements.
C．They have stronger chemical bonds than inorganic compounds do.
D．They are produced by linking several simple sugar molecules.Itwas(notuntil)afterEmilyDickinson'sdeat
It was (not until) after Emily Dickinson's death in 1886 that, (hidden away) in her bureau, (overly) one thousand unpublished poems (were discovered)A．not until
B．hidden away
C．overly
D．were discoveredAccordingtothepassage,themariadifferfrom
According to the passage, the maria differ from the terrace mainly in terms ofA．( age
B．( manner of creation
C．( size
D．( compositionA．(TrytoswitchhourswithsomeoneelseB．(Ask
A、( Try to switch hours with someone else
B、Ask his boss to raise his pay
C、Look of a more suitable job
D、Do the extra work without complainingHuntingisatbestaprecariouswayofprocuring
Hunting is at best a precarious way of procuring food, even when the diet is supplemented with seeds and fruits. Not long after the last IceAge, around 7,000
B、
C、(during the Neolithic period), some hunters and gatherers began to rely chiefly on agriculture for their sustenance. Others continued the old pastoral and nomadic ways. Indeed, agriculture itself evolved over the courseof(5) time, and Neolithic peoples had long known how to grow crops. The real transformation of human life occurred when huge numbers of people began to rely primarily and permanently on the grain they grew and the animals they domesticate
D、 Agriculture made possible a more stable and secure life. With it Neolithic peoples flourished, fashioning an energetic, creative er
A、They were responsible for many fundamental inventions and(10) innovations that the modern world takes for grante
D、First, obviously, is systematic agriculture-- that is, the reliance of Neolithic peoples on agriculture as their primary, not/nerely subsidiary, source of foo
D、 Thus they developed the primary economic activity of the entire ancient world and the basis of all modern life. With the settled routine of Neolithic farmers came the evolution of towns and(15) eventually cities. Neolithic farmers usually raised more food than they could consume, and their surpluses permitted larger, healthier populations. Population growth in turn created an even greater reliance on settled farming, as only systematic agriculture could sustain the increased numbers of people. Since surpluses o food could also be bartered for other commodities, the Neolithic era witnessed ihe beginnings of large-scale exchange of goods. In time the increasing(20) complexity of Neolithic societies led to the development of writing, prompted by the need to keep records and later by the urge to chronicle experiences, learning, and beliefs. The transition to settled life also had a profound impact on the family. The shared needs and pressures that encourage extended-family ties are less prominent in settled than in nomadic societies.Bonds to the extended family weakene
D、In towns and cities, the nuclear family was(25) more dependent on its immediate neighbors than on kinfolk.The word "settled" in line 15 is closest in meaning to
A、advanced
B、original
C、involved
D、stableA．Itwaswhatshehadexpected.B．Shemayneedan
A、It was what she had expecteD、
B．She may need a new floor.
C．She plans to vote forCarl,
D．She was very surpriseD、Thougharespectededucator,AlexanderGraham
Though a respected educator,Alexander GrahamBell ______ the inventor of the telephone.
A、as is best known
B、best known as is
C．is best known as
D．best is known asConsumerDemandandDevelopmentofGreenCarsT
ConsumerDemand andDevelopment of GreenCars
The day automakers put the earth at the top of their agenda will go down in history. Reading this book, one gets the sense that day is coming, major automakers—still no paragons of environmentalism—have gotten the message that replacing the dirty internal-combustion engine is an urgent priority. With less than 5 percent of the world’s population,Americans produce 14 percent of all global warming carbon-dioxide gas.And car tailpipes pump out more than 30 percent of U. S. air pollution.
In his new book, ForwardDrive: The Race toBuild "Clean"Cars for the Future, environmentalist Jim Motavalli concludes that capitalist competition is leading the way over government mandates to clean up that exhaust. Motavalli chronicles the movement for cleaner cars: the few visionaries and zealots building and driving home-built battery-powered cars; the divided giant automakers working tirelessly to develop clean cars while fighting regulatory efforts to require them; university researchers concluding studies; and the regulators trying to speed their adoption.
ForwardDrive covers the technological advances of the hybrid and fuel-cell vehicles poised to take over from the internal-combustion engine. In some ways, Motavalli is an unlikely narrator.A、self-vowed car nut who stumbled into a job editingE, theEnviromental Magazine, he seems biased on both sides of the issue.But ultimately, that’s what makes him best suited to tell this story.
Motoavalli’s concern for the environment is sincere, and his knowledge of cars is refreshingly accurate. The most interesting passages follow his transformattion from internal-combustion devotee to environmental auto cynic and battery-car zealot to hopeful future-car realist. "It was disconcerting, to say the least, to learn that my hobby of collecting classic cars and my growing concern for the environment didn’t necessarily mesh," Motavalli writes. "The car has certainly been good to me, but I’m becomin disenchanted."
In the preface, he noted that he set out to write a book critical of the auto industry for teaming up with major oil companies to block the development of clean cars.But when he dug in to do more research, he found a different story. Namely that automakers inDetroit, Japan, andEurope are in a heated race to start selling cars that are more environmentally correct.
A、[■] Unfortunately, Motavalli glosses over issues of consumer deman
D、
B、[■] He never mentions that today’s electric cars and gasoline-electric hybrids cost far more than internal-combustion cars of equal or greater capability.
C、[■] He notes their utter dedication to their electric cars and implies that the rest of the buying public should simply be as enthusiastic, without addressing issues of price or various ways families use their cars.
D、[■]
He strongly favorsCalifornia’s mandate that 10 percent of all vehicles sold in the state be zero-emission-vehicle-battery or fuel-cell electrics, not hybrids—even though he writes, "Ultimately, vehicles halfheartedly designed to meet a mandate would fail in the marketplace."And he gives a short shift to the point that clean cars do nothing to ease congestion and sprawl.
In a telephone interview, Motavalli concedes that technology is progressing faster than the book deadline allowed him to keep up with. If anything, automakers are working harder to develop hybrid-electrics.And mass-market hybrid-drive systems will likely first show up in the big sport utility vehicles that Motavalli rails against.
Nevertheless, he now believes that the automakers with the deepest pockets have the best chance of building better cars for tomorrow. "The new, clean cars will emerge not from a tinkerer’s garage, but from the well-funded research labs of the same big auto companies tLematin,elleprendunjusdefruitstoutdesuit
Le matin, elle prend un jus de fruits tout de suite après _________ . A．s'être démise
B．s'être rendu compte
C．s'être laissée
D． s'être levéeNorthAmericanGrasslandsInNorthAmerica,na
NorthAmerican Grasslands
In NorthAmerica, native grasslands occur primarily in the Great Plains in the middle of the continent. The NorthAmerican 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 toCanada 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 degreesCelsius (50 to 68 degrees Fahrenheit). In the moist regions of the NorthAmerican 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.
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. 
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 IceAge, when streams flowed in tunnels beneath glacially formed sandy ridges. When the IceAge 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.
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 SouthDakota, Montana,Alberta, Saskatchewan, and ManitobA、Prairie pothole country produces half of NorthAmerica’s 35 to 40 million ducks and is renowned worldwide as a "duck factory".
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 andCanada 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 theAn atom is a basic structural unit
An atom is a basic structural unit of matter, the smallest particle of an element （） into chemical combination.
A. that can enter
B. can it enter
C. when entering it can
D. that enters can{{B}}Set6BiologyLecture{{/B}}{{B}}Narrat
{{B}}Set 6Biology Lecture{{/B}}What is the main topic of the talkA．William Faulkner’s lifetime.
Listen to a lecture in the literature class.
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B．William Faulkner literature.
C．The birth of William Faulkner.
D．The poem of Faulkner.Allharmonizedmusicthatisnotcontrapuntald
All harmonized music that is not contrapuntal depends from the relationship of chords, which are either consonant or dissonant.ImportanceofVitaminsVitamins,whichcomein
Importance of Vitamins
Vitamins, which come in many different types all of which are quite diverse in chemical configuration and function, can be any of several organic substances that are separated into water-soluble and fat-soluble groups. Originally defined as organic compounds obtainable in a normal diet and capable of maintaining life and promoting growth, vitamins are differrent from carbohydrates, fats, and proteins in function, as well as in the quantities in which organisms require them. So critical are vitamins to a body’s essential strength and health that if they are absent from the diet or not properly absorbed by an organism, a specific deficiency disease may develop.
The term "vitamin" originated from "vitamine", a word first used in the early 19th century to designate a group of compounds considered vital for life (though the term "accessory food factor" sometimes is used interchangeably to refer to these substances). Like other nutrients, vitamin consumption is imperative to keep our bodies functioning properly, and if there is a lack of vitamin consumption, the body will fail to react in a way that’s considered healthy. Lack of vitaminA、will result in various disorders that most commonly involve the eye and the tissues around it. One of the earliest symptoms of vitaminA、deficiency is nyctalopia, the medical term for night blindness, which causes a visual failure to adapt quickly from light to darkness and an inability to see in the dark. This aspect of vision is normally dependent on rhodopsin, a protein found in the eye that maintains itself only in the presence of vitaminA; in the lack of vitaminA, rhodopsin will malfunction.
These earlier symptoms are quite harmless but the side effects can become increasingly serious if not treated early on. If the deficiency is severe and persists, especially in malnourished infants and children, a condition known as xerophthahnia--when the eyes are sensitive to light, the secretion of lubricating tears is stopped, and the eyelids become swollen and develop pus--may develop. Furthermore, the mucous surfaces of the eye may become eroded, allowing infection to set in, thus leading to ulceration and other destructive changes of the cornea and other structures of the eye, resulting eventually in blindness.
Early signs of vitaminA、deficiency may also be reflected in changes in the membranes of the mouth, throat, and respiratory and genitourinary passages where the lining membranes become malnourished and dry and lose their cilia, the tiny hairlike projections that normally help in clearing away foreign particles. 
The natural immune system is weakened and if insufficient intake of vitaminA、is prolonged, the skin may become dry and rough. 
VitaminA、deficiency may also result in defective bone and teeth formation and in poor general growth. 
However, an excessive intake of vitaminA、can also cause severe damages to the body causing a symptom called "hypervitaminosisA", which happens when a person takes in more than 150 milligrams of vitaminA、over a long period of time; the vitamins are stored in the liver and can reach dangerous level because theA、vitamins are not employed to make the bodies stronger, but rather, stored as toxic material.Excessive amounts of vitaminA、can cause nausea, dryness of skin, blurred vision, drowsiness, and bone pain.
VitaminA、can be found in all animal livers, in milk products, and in many yellow and green leafy vegetables which contain carotenes, chemically related substances that are converted to vitaminA、in the body. There are various other vitamins that the humQuestions22-31:Thefirstpeoplestoinhabitw
Questions 22-31:The first peoples to inhabit what today is the southeastern United States sustained themselves as hunters and gathers. Sometimes early in the first millennium
A、D、, however, they began to cultivate corn and other crops. Gradually, as they became more skilled at gardening, they settled into permanent villages and developed a rich culture, characterized by the great earthen mounds they erected as monuments to their gods and as tombs for their distinguished deaD、Most of these early mound builders were part of theAdena-Hopewell culture, which had its beginnings near the Ohio River and takes its name from sites in Ohio. The culture spread southward into the present-day states of Louisiana,Alabama, Georgia, and Florid
A、Its peoples became great traders, bartering jewellery, pottery, animal pelts, tools, and other goods along extensive trading networks that stretched up and down eastern NorthAmerica and as far west as the Rocky Mountains.About
A、D、400, the Hopewell culture fell into decay. Over the next centuries, it was supplanted by another culture, the Mississippian, named after the river along which many of its earliest villages were locateD、This complex civilization dominated the Southeast from about
A、D、700 until shortly before theEuropeans began arriving in the sixteenth century.At the peak of its strength, about the year 1200, it was the most advanced culture in NorthAmeric
A、Like their Hopewell predecessors, the Mississippians became highly skilled at growing food, although on a grander scale. They developed an improved strain of corn, which could survive in wet soil and a relatively cool climate, and also learned to cultivate beans. Indeed, agriculture became so important to the Mississippians that it became closely associated with the Sun --- the guarantor of good crops. Many tribes called themselves "children of the Sun" and believed their omnipotent priest-chiefs were descendants of the great sun goD、Although most Mississippians lived in small villages, many others inhabited large towns. Most of these towns boasted at least one major flat-topped mound on which stood a temple that contained a sacred flame. Only priests and those charged with guarding the flame could enter the temples. The mounds also served as ceremonial and trading sites, and at times they were used as burial grounds.The word "bartering" in line 9 is closest in meaning to
A、producing
B．exchanging
C．transporting
D．loadingComingSoon:theNextGreatFluEpidemicThevir
Coming Soon: the Next Great FluEpidemic
The virus first came to officials’ attention in a bag of dead chickens.Early in March 1997, a farmer from Hong Kong’s New Territories carried them into theAgriculture and FisheriesDepartment laboratory. The final state of some birds was a hideous, bloody mush.Cultures of their organs revealed they had died of avian influenza, type H5N1. Influenza of the H5 subtype had never been known to infect humans.But in the next seven months, 18 Hong Kong residents fell ill with H5N1 and six dieD、
In lateDecember 1997, public health officials took a drastic step, ordering the slaughter of every chicken in every farm and marketplace in Hong Kong. The HSN1 virus seemed to disappear but for how long
The specter of the 1918 flu was raised by this new avian flu. The 1918 flu was one of the most changeable and resistant viruses known to man.After we’ve been infected with one strain, it can mutate and infect us again. We are only immune to flu strains our bodies have seen before.
A、flu can also "jump species" to an animal it has never infected before, once such a flu moves into humans, if it can "learn" to pass easily between them, it can spark a pandemic—a global outbreak.
Birds carry the flu virus in their intestines and excrete it in their feces. In all likelihood, shoppers who got sick with H5 touched surfaces contaminated with chicken feces. Humans, however, carry flu in their respiratory tracts and usually spread them in a cough or sneeze. Flu strains that travel this way are highly contagious.
The H5 virus in Hong Kong was different. It sickened very few, but killed a third of those infecteD、Most who got sick with H5 seemed to catch it directly from a bird they bought in a live-poultry market.
After the Hong Kong outbreak, flu experts feared that H5—already deadly to humans—might learn to move between humans as well as between birds. That "raises the specter of 1918", says NancyCox, chief of the InfluenzaBranch of the U. S.Centers forDiseaseControl and PreventionCDCP).
Geographic isolation was no protection during the 1918 pandemiC、In theAlaska Territory, the mortality rate in some villages was as high as 90 percent.All told, at least 500000Americans perisheD、It could happen again.
The virus that became the Spanish flu probably came from a birD、Avian-flu expertDr. Robert Webster of St. JudeChildren’s Research Hospital in Memphis, Tenn., believes the virus may have leapt straight from birds to humans, possibly a year to two before the pandemic began. Once lodged in human lungs, it quickly passed from person to person in a simple cough or sneeze. To avoid that grim possibility, here are three measures all nations need to take:
The first step is better surveillance. Most countries, though, don’t start tracking avian flu until after an epidemic kills their chickens. The United States dramatically increased its monitoring after a deadly outbreak in Pennsylvania in the early 1980s. The USDA、(United StatesDepartment ofAgriculture) provides diagnostic support. Some virologists recommend enhancing surveillance of swine flu too. The U. S. National Institutes of Health is beginning to study the issue.
Elsewhere, the coverage is not good enough, saysDr. W. Paul Glezen of theBaylorCollege of Medicine’s Influenza ResearchCenter. He namesAfrica and SouthAmerica as areas where the World Health Organizations net is incomplete.
Another important measure is producing more vaccines and flu shots. Only three of the 15 known influenza subtypes—H1, H2 and H3—have been found in people. Vaccines exist for each, and an H5 vaccine is now being developeD、Some experts believe that we should develop a vaccine for the other known subtypes as well.
Health authorities add that more people need flu shots now. We should manufacture 120 million doses a year1Ahotspotisagiantundergroundcaldronofmol
1
A、hot spot is a giant underground caldron of molten rock in one of the world’s many volcanically active areas. The steamy~ geysers, thermal pools, and mud pots of Yellowstone National Park owe their origins to hot spots.
2Annually, more than 200 geysers erupt in Yellowstone, making this one of the most interesting places in the world for geologists. Over 100 geysers lie within the Upper GeyserBasin, a one-square-mile area near Old Faithful, the most famous geyser in the worlD、The Yellowstone hot spot was created around ten million years ago, and the center of the park is still volcanically active, with molten rock only a mile or two beneath theEarth’s surface.
3 When rain and melted snow seep down through tiny cracks in theEarth, the water eventually reaches underground chambers of lava-heated rock. The rock heats the water, and the boiling water and steam often make their way back up to the surface in the form of a geyser, a thermal pool, or a mud pot.
4 In a geyser, water trapped in an underground chamber heats up beyond the boiling point and forms steam. Since steam takes up 1,500 times more space than water, pressure builds up, eventually forcing the superheated water to burst to the surface as a geyser.
A、thermal pool is formed when the water from the hot spot reaches the surface before cooling off. If the water does not make it all the way to the surface, steam and gases may dissolve rocks and form a bubbling mud pot insteaD、
Where do hot spots occur
A、In rocky regions near the equator
Below the ground near active volcanoes
C．About a mile above a volcano’s crater
D．In the center of ancient volcanoes(a)Shemaychangehermindaboutthecollege(b)
(a) She may change her mind about the college(b) He doesn’t know what time she arrived(c) He wishes he had met her yesterday(d) She should visit the campus again soon