Listening6"HistoryClass"{$mediaurl}Whydo
Listening 6 "HistoryClass"
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Why does the professor say this:
A、To criticize the sod house
B、To demonstrate uncertainty
C、To draw a conclusion
D、To uphold an opinionManyantsforageacrossthecountrysideinlarg
Many ants forage across the countryside in large numbers and undertake massmigrations; these activities proceed because one ant lays a trail on the ground for the othersto follow.As a worker ant returns home after finding a source of food, it marks the route by intermittently touching its stinger to the ground and depositing a tiny amount of trail(5)pheromone—a mixture of chemicals that delivers diverse messages as the context changes. These trails incorporate no directional information and may be followed by other ants in either direction.Unlike some other messages, such as the one arising from a dead ant, a food trail has to be kept secret from members of other species. It is not surprising then that ant species use(10)a wide variety of compounds as trail pheromones.Ants can be extremely sensitive to thesesignals. Investigators working with the trail pheromone of the leafcutter antAtta texana calculatedthat one milligram of this substance would suffice to lead a column of ants three times around Earth.The vapor of the evaporating pheromone over the trail guides an ant along the way, (15)and the ant detects this signal with receptors in its antennae.
A、trail pheromone will evaporate to furnish the highest concentration of vapor right over the trail, in what is called avapor space. In following the trail, the ant moves to the right and left, oscillating from sideto side across the line of the trail itself, bringing first one and then the other antenna intothe vapor space.As the ant moves to the right, its left antenna arrives in the vapor space. (20)The signal it receives causes it to swing to the left, and the ant then pursues this new courseuntil its right antenna reaches the vapor space. It then swings back to the right, and so weaves back and forth down the trail. The author mentions the trail pheromone of the leafcutter ant in line 11 to point out
A、how little pheromone is needed to mark a trail
B．the different types of pheromones ants can produce
C．a type of ant that is common in many parts of the world
D．that certain ants can produce up to one milligram of pheromoneA．(Thetaskwilltakemoretimethanthemanthin
A、( The task will take more time than the man thinks
B、She doesn’t want to talk with the man while he’s angry
C、She can’t help the man until later
D、she want to know why the man didn’t come earlierBiologicalBarriersandPathwaysVirtuallyal
BiologicalBarriers and Pathways
Virtually all living things have some way of getting from here to there.Animals may walk, swim, or fly. Plants and their seeds drift on wind or water or are carried by animals. Therefore, it is reasonable to expect that, in time, all species might spread to every place onEarth where favorable conditions occur. Indeed, there are some cosmopolitan species.A、good example is the housefly, found almost everywhere onEarth. However, such broad distribution is the rare exception. Just as barbed wire fences prevent cattle from leaving their pasture, biological barriers prevent the dispersal of many species.
What constitutes barriers depends on the species and its method of dispersal. Some are physical barriers. For land animals, bodies of water, chains of mountains, or deserts are effective. For example, theAmerican bison spread throughout the open grasslands of NorthAmerica, but in the southern part of the continent there are deserts, so the bison could not spread there. For aquatic creatures, strong currents, differences in salinity, or land areas may serve as barriers.
Some barriers involve competition with other species.A、dandelion seed may be carried by the wind to bare ground, and, if environmental factors are right, it may germinate. There is not much chance, however, that any individual seedling will survive. Most places that are suitable for the growth of dandelions are already occupied by other types of plants that are well adapted to the areA、The dandelion seedling must compete with these plants for space, water, light, and nutrients. Facing such stiff competition, the chances of survival are slim.
For animals, some barriers are behavioral, The blue spotted salamander lives only on mountain slopes in the southernAppalachian Highlands.Although these creatures could survive in the river valleys, they never venture there.Birds that fly long distances often remain in very limited areas. Kirkland’s warblers are found only in a few places in Michigan in the summer and fly to theBahamas in winter. No physical barriers restrict the warblers to these two locations, yet they never spread beyond these boundaries.Brazil’sAmazon River serves as a northern or southern boundary for many species of birds. They could freely fly over the river, but they seldom do.
There are three types of natural pathways through which organisms can overcome barriers. One type is called a corridor.A、corridor consists of a single type of habitat that passes through various other types of habitat. NorthAmerica’s Rocky Mountains, which stretch fromAlaska to northern Mexico, is an example. Various types of trees, such as theEngehnann spruce, can be found not only at the northern end of the corridor inAlaska but also at higher elevations along the entire length of this corridor.
A、second type of natural pathway is known as a filter route.A、filter route consists of a series of habitats that are different from one another but are similar enough to permit organisms to gradually adapt to new conditions as they spread from habitat to habitat. The greatest difference between a corridor and a filter route is that a corridor consists of one type of habitat, while a filter consists of several similar types.
The third type of natural pathway is called a sweepstakes route. This is dispersal caused by the chance combination of favorable conditions.Bird watchers are familiar with "accidentals", which are birds that appear in places far from their native areas.
Sometimes they may find a habitat with favorable conditions and "colonize" it. Gardeners are familiar with "volunteers", cultivated plants
Byfocusingontheinteresting,______thesign
By focusing on the interesting, ______ the significant, the penny press newspapers of the 1830's helped to change the concept of news.A．(which does not necessarily
B．(not necessarily
C．(was not necessarily
D．(nor necessarily beingA．Itisn’’tnecessarytoattendthelecture.B．
A、It isn’’t necessary to attend the lecture.
B．There isn’’t enough time to eat dessert
C．Eating in the lecture hall is prohibite
D、
D、The lecture probably won’’t start on time.{$mediaurl}WhatisthelecturemainlyaboutA．
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What is the lecture mainly aboutA．Real estate prices.
B．Campbell monkeys’ eating habits.
C、The interactions of various species.
D．The relationship betweenDiana and putty-nosed monkeys.独立写作：人要多渠道获取信息
独立写作：人要多渠道获取信息Thephrase"subscribedto"inline8isclosesti
The phrase "subscribed to" in line 8 is closest in meaning to(a) contributed to(b) agreed with(c) thought about(d) expanded on{$mediaurl}[*][*]Listenagaintopartofthet
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[*] Listen again to part of the talk. Then answer the question.
Why does the professor say this:
A．To point out the diversity of plant life
B．To give an example of an environmental cue
C．To compare different ecosystems where plants live
D．To explain why few plants survive in the desertBeforetheEuropeansarrived,AmericanIndian
Before theEuropeans arrived,American Indians were using virgin copper ______ into ornaments, knives, and other artifacts.
A、Which was hammering
B．which hammered
C．was hammered
D．hammeredA．(HelpthewomanrepairhercarB．(Helpthewom
A、( Help the woman repair her car
B、Help the woman find a job
C、Cancel the woman’s appointment for her
D、Take the woman to her doctor’s office.Woodfromtheashtreebecomesextremelyflexi
. Wood from the ash tree becomes extremely flexibly when it is exposed to steam. A B C DQuestions44-50Asthetwentiethcenturybegan
Questions 44-50As the twentieth century began, the importance of formal education in the UnitedStates increased The frontier had mostly disappeared and by 1910 mostAmericanslived in towns and cities. Industrialization and the bureaucratization of economicline life combined with a new emphasis upon credentials and expertise to make schooling increasingly important for economic and social mobility. Increasingly, too, schoolswere viewed as the most important means of integrating immigrants intoAmericansociety.The arrival of a great wave of southern and easternEuropean immigrants at the turnof the century coincided with and contributed to an enormous expansion of formal schooling.By 1920 schooling to age fourteen or beyond was compulsory in moststates, nd the school year was greatly lengtheneD、Kindergartens, vacation schools,extracurricular activities, and vocational education and counseling extended theinfluence of public schools over the lives of students, many of whom in the largerindustrial cities were the children of immigrants.Classes for adult immigrants were sponsored by public schools, corporations, unions, churches, settlement houses, andother agencies.Reformers early in the twentieth century suggested that education programs shouldsuit the needs of specific populations. Immigrant women were one such population.Schools tried to educate young women so they could occupy productive places in theurban industrial economy, and one place many educators considered appropriate forwomen was the home.Although looking after the house and family was familiar to immigrant women,American education gave homemaking a new definition. In preindustrial economies,homemaking had meant the production as well as the consumption of goods, and it commonly included income-producing activities both inside and outside the home,in the highly industrialized early-twentieth-century United States, however,overproduction rather than scarcity was becoming a problem. Thus, the idealAmericanhomemaker was viewed as a consumer rather than a producer. Schools trained womento be consumer homemakers cooking, shopping, decorating, and caring for children "efficiently" in their own homes, or if economic necessity demanded, as employeesin the homes of others. Subsequent reforms have made these notions seem quiteout-of-date.It can be inferred from paragraph 1 that oneimportant factor in the increasing importanceof education in the United States was
A、the growing number of schools in frontiercommunities
B、an increase in the number of trainedteachers
C、the expanding economic problems ofschools
D．the increased urbanization of the entirecountryAirlineAlliancesCooperativecompetition.C
AirlineAlliances
Cooperative competition.Competitive cooperation.ConfusedAirline alliances have travelers scratching their heads over what’s going on in the skies. Some folks view alliances as a blessing to travelers, offering seamless travel, reduced fares and enhanced frequent-flyer benefits. Others see a conspiracy of big businesses, causing decreased competition, increased fares and fewer choices. Whatever your opinion is, there are no escaping airline alliances: the marketing hype is unrelenting, with each of the two mega-groupings. Oneworld and StarAlliance promote themselves as the best choice for all travelers.And, even if you turn away from their ads, chances are they will figure in any of your travel plans.
But why, after years of often ferocious competition, have airlines decided to band together Let’s just say the timing is mutually convenient. NorthAmericanAirlines, having exhausted all means of earning customer loyalty at home, have been looking for ways to reach out to foreign flyers.Asian carriers are still hurting from the region—the wide economic downturn that began two years ago just when some of the airlines were taking delivery of new aircraft.Alliances also allow carriers to cut costs and increase profits by pooling manpower resources on the ground (rather than each airline maintaining its own ground crew) and code-sharing—the practice of two partners selling tickets and operating only one aircraft.
So alliances are terrific for airlines—but are they good for the passengerAbsolutely, say the airlines: think of the lounges, the joint FFP (frequent flyer programme) benefits, the round-the-world fares, and the global service networks. Then there is the promise of "seamless" travel: the ability to, say, travel from Singapore to Rome to New York to Rio de Janeiro, all on one ticket, without having to wait hours for connections or worry about your bags. Sounds Utopian PeterBuecking,Cathay Pacific’sDirector of Sales and Marketing, thinks that seamless travel is still evolving. "The key to seamlessness rests in infrastructure and information sharing. We are working on this." Henry Ma, spokesperson for StarAlliance in Hong Kong, lists some of the other benefits for customers: "Global travelers have an easier time making connections and planning their itineraries." Ma claims alliances also assure passengers consistent service standards.
Critics of alliances say the much touted benefits to the customer are mostly pie in the sky, that alliances are all about reducing costs for the airlines, rationalizing services and running joint marketing programmes. Consumer Report’s SeniorEditor JeffBlyskal says the promotional ballyhoo over alliances is much ado about nothing. "I don’t see much of a gain for consumers: alliances are just a marketing gimmick. Most airlines can not even get their own connections under control, let alone coordinate with another airline. "
Blyskal believes alliances will ultimately result in decreased flight choices and increased costs for consumers. Instead of two airlines competing and each operating a flight on the same route at 70% capacity, the allied pair will share the route and run one full flight. Since fewer seats will be available, passengers will be obliged to pay more for tickets.
The truth about alliances and their merits probably lies somewhere between the travel Utopia presented by the players, and the evil empires portrayed by their critics.And how much they affect you depends on what kind of traveler you are.
Those who’ve already made the elite grade in the FFP of a major airline stand to benefit the most when it joints an alliance: then they enjoy the FFP perks and advantages on any and all of the member carriers. For example, if you are a Marco PoloClub "gold" member ofCathay Pacific’sAsia Miles FFP, you will automatically be treated as a valuGourdswere(introduced)towhatisnowthesout
Gourds were (introduced) to what is now the southwestern United States by (earliest) peoples (who) migrated north (from) Mesoamerica about 7000 years ago.
A、introduced
B．earliest
C．who
D．fromBenjaminGrahamBenjaminGrahamwasanotedeco
Benjamin Graham
Benjamin Graham was a noted economist who formulated his theories on stock market investment in response to the great stock market collapse of 1929. Specifically, he viewed the collapse of the stock market as a result of people following market trends too closely. In fact, he often used a character called "Mr. Market" in his works to demonstrate how foolish it was to simply fall into line with market trends. If a person called "Mr. Market" appeared on your doorstep each day and offered random prices for various stocks, you would not accept every offer he made, since some of those offers would be utterly ridiculous. Instead,Benjamin Graham argued, a person who wishes to do well in the stock market should seek out stocks that are being sold for less than their value should be in a rational market. This was something he called value investing. The problem, of course, lies in figuring out what a stock’s ideal value should be. To do this, Graham believed that before buying a stock, an investor should analyze that company’s assets and liabilities to determine its true financial situation. If that situation looked good, and seemed as if it should allow the company to command a higher stock price than it was actually charging, then it was a good buy.
When it came to determining which stocks were below ideal market value,Benjamin Graham emphasized studying those aspects of a company that were easily quantifiable. In his original version of the theory of value investing, he simply looked for stocks that were trading for slightly less than their so-called "book value."A、company’s book value is how much net worth it has according to its accounting books, which list all of its liabilities, expenses, revenue, and assets. Most economists later viewed this as a flawed approach, since some assets, such as computers, tractors, and cars, depreciate in value almost as soon as they are acquireD、They argued that the value of a company’s assets should be measured not by their book value, but by how much money they were likely to make the company in future. Others pointed out that some industries are so unstable that it is difficult to meaningfully quantify the assets of the companies involved in them. Still others have criticized Graham’s theory for ignoring factors that cannot be easily quantified, such as the quality of a company’s leadership.Despite this criticism, studies have shown that value investing seems to increase an investor’s chance of making money on the stock exchange.
To most people today, Graham’s basic theory may seem like little more than common sense; yet there are still many investors who allow themselves to get caught up in the excitement of market fluctuations and who stop making rational investment decisions. We see this in the creation and bursting of stock bubbles.A、stock bubble occurs when people focus purely on market trends without stopping to examine the actual worth of the companies whose stock they are buying. Normally, this is driven by a belief that companies
in a certain sector are on the verge of a breakthrough that will drive their profits up. Investors pour money into buying these companies’ stocks, which drives up the stocks’ price. This in turn makes their investment seem good to others, who then follow suit, driving the price up even higher and encouraging still more people to invest in those stocks. This upward cycle cannot continue indefinitely, however.Eventually, the stock prices are so much higher than those companies’ financial positions should allow that some of the investors get nervous and start selling stock. The prices then begin to drop, and everyone involved panics, trying to sell at the same time, rendering those stocks virtually worthless.
In a very real sense, the stock market crash that launched the GreatDepression was a result of the first stock market bubble bursting. The problem was that since no one knew ab综合写作讲H文明的灭绝。阅读讲因为1，被入侵2，气候3，疾病，叫做chorelo
综合写作 讲H文明的灭绝。 阅读讲因为1， 被入侵 2， 气候 3， 疾病，叫做 chorelo之类的。教授就全部否定此三点。UndertheEarth’’stopsoil,atvariouslevels,
Under theEarth’’s topsoil, at various levels, sometimes under a layer of rock, there am deposits of clay. Look at cuts where highways have been built to see exposed clay beds; or look at a construction site, where pockets of clay may be exposeD、Rivers also reveal clay along their banks, and erosion on a hillside may make clay easily accessible.(5) What is clay made oF TheEarth’’s surface is basically rock, and it is this rock that gradually decomposes into clay. Rain, streams, alternating freezing and thawing, roots of trees and plants forcing their way into cracks, earthquakes, volcanic action, and glaciers-all of these forces slowly break down theEarth’’s exposed rocky crust into smaller and smaller pieces that eventually become clay.(10) Rocks are composed of elements and compounds of elements. Feldspar, which is the most abundant mineral on theEarth’’s surface, is basically made up of the oxides silica and alumina combined with alkalies like potassium and some so-called impurities such as iron. Feldspar is an essential component of granite rocks, and as such it is the basis of clay. When it is wet, clay can be easily shaped to make a variety of useful objects, which can(15) then be fired to varying degrees of hardness and covered with impermeable decorative coatings of glasslike material called glaze. Just as volcanic action, with its intense heat, fuses the elements in certain rocks into a glasslike rock called obsidian, so can we apply heat to earthen materials and change them into a hard, dense material.Different clays need different heat levels to fuse, and some, the low-fire clays, never become nonporous and(20) watertight like highly fired stoneware.Each clay can stand only a certain amount of heat without losing its shape throughsagging or melting. Variations of clay composition and the temperatures at which they are fired account for the differences in texture and appearance between a china teacup and an earthenware flowerpot.It can be inferred from the passage that clay is LEAST likely to be plentiful in which of the following areas
A、In desert sand dunes
B．In forests
C．On hillsides
D．Near riversPeoplerememberspecialgiftsorpresentsthat
People remember special gifts or presents that they have receiveD、Why Use specific reasons and examples to support your answer.