单选题The author mentions Renoir in line 25 to give an example of an artist who

单选题The word "endless" in line 14 is closest in meaning to

单选题According to the passage, which of the following do squirrels and blue jays have in common?

单选题1 The human ear contains the organ for hearing and the organ for balance. Both organs involve fluid-filled channels containing hair cells that produce electrochemical impulses when the hairs are stimulated by moving fluid. 2 The ear can be divided into three regions: outer, middle, and inner. The outer ear collects sound waves and directs them to the eardrum separating the outer ear from the middle ear. The middle ear conducts sound vibrations through three small bones to the inner ear. The inner ear is a network of channels containing fluid that moves in response to sound or movement. 3 To perform the function of hearing, the ear converts the energy of pressure waves moving through the air into nerve impulses that the brain perceives as sound. Vibrating objects, such as the vocal cords of a speaking person, create waves in the surrounding air. These waves cause the eardrum to vibrate with the same frequency. The three bones of the middle ear amplify and transmit the vibrations to the oval window, a membrane on the surface of the cochlea, the organ of hearing. Vibrations of the oval window produce pressure waves in the fluid inside the cochlea. Hair cells in the cochlea convert the energy of the vibrating fluid into impulses that travel along the auditory nerve to the brain. 4 The organ for balance is also located in the inner ear. Sensations related to body position are generated much like sensations of sound. Hair cells in the inner ear respond to changes in head position with respect to gravity and movement. Gravity is always pulling down on the hairs, sending a constant series of impulses to the brain. When the position of the head changes--as when the head bends forward--the force on the hair cells changes its output of nerve impulses. The brain then interprets these changes to determine the head's new position.

单选题The care of children during their years of relative helplessness appears to have being the chief incentive for the evolution of family structures.

单选题1 So much sentimentality is attached to the rose in popular culture that it is difficult to separate the original mythological and folkloric beliefs from the emotional excess that surrounds the flower~ Yet if we look into the beliefs, we find that the rose is much more than the mere symbol of romantic love invoked by every minor poet and painter 2 One of the rose's most common associations in folklore is with death. The Romans often decked the tombs of the dead with roses; in fact, Roman wills frequently specified that roses were to be planted on the grave. To this day, in Switzerland, cemeteries are known as rose gardens. The Saxons equated the rose with life, and they believed that when a child died, the figure of death could be seen plucking a rose outside the house. 3 The rose has a long association with female beauty. Shakespeare mentions the rose more frequently than any other flower, often using it as a token of all that is lovely and good. For the Arabs, on the other hand, the rose was a symbol not of feminine but of masculine beauty. 4 Later the rose became a sign of secrecy and silence. The expression sub rosa, "under the rose," is traced to a Roman belief. During the sixteenth and seventeenth centuries, it was common practice to carve or paint roses on the ceilings of council chambers to emphasize the intention of secrecy.

单选题1 In the nineteenth century, Americans were becoming more familiar with European homes and luxuries. When "period" furniture became popular, American furniture factories attempted to duplicate various styles of French and English furniture of the seventeenth and eighteenth centuries. At the same time, designers in England were attempting a return to handicrafts as a means of self-expression. William Morris and other leaders of the English Arts and Crafts movement created home furnishings that celebrated the individuality of the designer. 2 In the United States, a similar movement soon followed. The American Arts and Crafts-or Craftsman--movement was based not only on individualism but also on a return to simplicity and practicality. Like the Arts and Crafts furniture in England, the Craftsman furniture in America represented a revolt from mass-produced furniture. Makers of Craftsman furniture sought inspiration in human necessity, basing their furniture on a respect for the sturdy and primitive forms that were meant for usefulness alone. 3 Gustav Stickley, pioneer of the Craftsman movement, believed that average working people wanted furniture that was comfortable to live with and would also be a good investment of money. Stickley felt that any American style in furniture would have to possess the essential qualities of durability, comfort, and convenience. Craftsman furniture was plain and unornamented--made to look as if the common man could build it himself in his own workshop. Locally obtained hardwoods and simple, straight lines were the hallmarks of its construction. The severity of the style departed greatly from the ornate and pretentious factory-made "period" furniture that had dominated in homes up till then.

单选题[此试题无题干]

单选题The average elevation of West Virginia is about 1,500 foot above sea level.

单选题By about seven years of age, children begin to grasp that a given quantity remains A B the same not matter how its shape changes. C D

单选题Listentopartofaconversationbetweenastudentandaprofessor.Nowgetreadytoanswerthequestions.Youmayuseyournotestohelpyouanswer.Listenagaintopartoftheconversation.Thenanswerthequestion.

单选题Cultural Shock "Culture shock" might be called an occupational disease of people who have been suddenly transplanted abroad. Like most ailments, it has its own symptoms and cure. Culture shock is precipitated by the anxiety that results from losing all our signs and symbols of social intercourse. Those signs or cues include the thousand and one ways in which we orient ourselves to the situation of daily life; when to shake hands and what to say when we meet people, when and how to give tips, how to make purchases, when to accept and when to refuse invitations, when to take statements seriously and when not. Now when an individual enters a strange culture, all or most of these familiar cues are removed. He or she is like a fish out of water. No matter how broad-minded or full of goodwill you may be, a series of props has been knocked out from under you, followed by a feeling of frustration and anxiety. People react to the frustration in much the same way. First they reject the environment which causes the discomfort. "The ways of the host country are bad because they make us feel bad." When foreigners in a strange land get together to grouse about the host country and its people, you can be sure they are suffering from culture shock. Another phase of culture shock is regression. The home environment suddenly assumes a tremendous importance. To the foreigner everything becomes irrationally glorified. All the difficulties and problems are forgotten and only the good things back home are remembered. It usually takes a trip home to bring one back to reality. Individuals differ greatly in the degree in which culture shock affects them.(A) [■] Although not common, there are individuals who cannot live in foreign countries.(B) [■] During the first few weeks most individuals are fascinated by the new.(C) [■] They stay in hotels and associate with nationals who speak their language and are polite and gracious to foreigners.(D) [■] This honeymoon stage may last from a few days or weeks to six months, depending on circumstances. If one is very important, he or she will be brought to visit the show places, will be pampered and petted, and in a press interview will speak glowingly about goodwill and international friendship. But this mentality does not normally last if the foreign visitor remains abroad and needs to seriously cope with real conditions of life. It is then that the second stage begins, characterized by a hostile and aggressive attitude toward the host country. This hostility evidently grows out of the genuine difficulty which the visitor experiences in the process of adjustment. There are house troubles, transportation troubles, shopping troubles, and the fact that people in the host country are largely indifferent to all these troubles. They help, but they don't understand your great concern over these difficulties. Therefore, they must be insensitive and unsympathetic to you and your worries. The result, "I just don't like them." You become aggressive, you band together with others from your country and criticize the host country, its ways, and its people. But this criticism is not an objective appraisal. You take refuge in the colony of others from your country which often becomes the fountainhead of emotionally charged labels known as stereotypes. This is a peculiar kind of offensive shorthand which caricatures the host country and its people in a negative manner. The "dollar grasping American" and the "indolent Latin American" are samples of mild forms of stereotypes. The second stage of culture shock is, in a sense, a crisis in the disease. If you come out of it, you leave before you reach the stage of a nervous breakdown. If visitors succeed in acquiring some knowledge of the language and begin to get around by themselves, they are beginning to open the way into the new cultural environment. Visitors still have difficulties but they take a "this is my problem and I have to bear it" attitude. Usually in this stage visitors take a superior attitude to people of the host country. Their sense of humor begins to exert itself. Instead of criticizing, they joke about the people and even crack jokes about their own difficulties. They are now on the way to recovery.

单选题A sponge feeds itself by drawing water through tiny pores on its surface, filtering out food particles, and then expel the water through larger vents.

单选题Listentopartofalectureinaneconomicsclass.Nowgetreadytoanswerthequestions.Youmayuseyournotestohelpyouanswer.

单选题Listentopartofaconversationbetweentwostudents.Nowgetreadytoanswerthequestions.Youmayuseyournotestohelpyouanswer.Listenagaintopartoftheconversation.Thenanswerthequestion.

单选题{{B}}Lichens{{/B}}Tobecertain,alichenisnotthemostconspicuousofplants.Lichensgrowinunassumingfashiononrocks,logsandotherexposedsurfacesinawiderangeofhabitatsaroundtheworld.Totheuntrainedeyetheylooklikelittlemorethancrustypatchesthat,atfirstglance,mighteasilybemistakenforadiscolorationofthesurface.Eveniftheaveragepersonshouldhappentonoticethelichen'spresenceandcorrectlyidentifyitassomeformoflife,heisunlikelytogomuchfurtherincontemplatingit.Thoughalmosttotallyignoredbythelayperson,forthebotanist,lichensareoneofthemostfascinatingofallplants,andoneofthemostintenselystudied.Theyarethesubjectofsomuchscientificscrutinyprimarilybecausealichenisnotjustoneplant.Itis,infact,acompositeorganismmadeupoffungusandalgaelivingtogetherinacloseassociationthatis,presumably,beneficialtoboth.Whenthesetwoverydifferentplantscombine,theresultisauniqueandverylong-livedcompositeorganismthatappears,atleastonamacroscopicscale,tobeaunitaryplant.Itisanorganismthatbearsnoresemblancetoeitherofitsconstituentswhentheyareobservedindividually.Theseparatefungalandalga)elementscanberecognizedonlywhenthebodyoftheplant,calledathallusbecausetherearenostemsorroots,issectionedandexaminedunderamicroscope.Whenviewedthisway,thefunguscomponentdominatesthepicture,asitaccountsforninetenthsofthetotalbodymassofthelichen.But,entrappedwithinit,clearlyvisibleasdarkspots,arethealgaecells.Essentially,nothingisknownofhowanamorphousmassoffungiandalgaecometogethertoformahighlydifferentiated,structurallystablebody.Despiteallthescientificscrutinylichenshavereceived,itisstillnotentirelycertainwhateachmembergainsfromtheassociation.Someresearchershavespeculatedthatthefungijoinintherelationshipbecausetheyareabletoconsumethealgaecellsastheydieandthereforeareguaranteedafoodsupply.Itiswell-knownthatthechlorophyll-containingalgaecellsproducefoodbymeansofphotosynthesis.Theremaybesomemechanism,stillunknowntous,throughwhichthisenergysourceisutilizedbythefungus.Funguspossessesnochlorophyllofitsown.Howorevenwhetherthealgaebenefitfromthisassociationisstilllesscertain,thoughwecaneasilyimaginethattheygainmechanicalprotectionfromtheelementsbybeingtightlyenvelopedinthestructuralfibersofthefungusbody.Theyshouldalsobenefitfromretentionofwaterbetweenthefibers.Thehardinessoflichenshasmadethemwhatbotaniststerm"pioneerplants".Thisreferstotheirabilitytocolonizehabitatswhereotherplantsdonotexist.Theyarecommononbarrenrockysurfaces,wherethelackofsoilprecludestheestablishmentofmostotherkindsofplantlife.TheycanevenbefoundinplacesashostileandextremeastheinterioroftheAntarcticcontinent.Althoughtheyaremostoftenassociatedwithfarnorthernorsouthernenvironments,theyhavebeenfoundlivinginsunbakeddesertsoilsthatareotherwisedevoidoflife.ThemosthighlyspecializedlichensaretheendolithicspeciesoftheAntarctic,whichasthenameindicates,liveinsiderocks,formingmoreorlesscontinuoustissuestructuresbetweentherockcrystals.Asremarkableintheirrobustnessaslichensare,thereisonekindofanenvironmentwhichtheyaregenerallyunabletotolerate.Habitatsthatareheavilyaffectedbypollutionaxenoticeablydevoidoflichens.Theseorganismsareespeciallysusceptibletosulfurdioxidepoisoningandtheyabsorbandaccumulateothertoxinsaswell;bothairandwaterborne.Thisheightenedsensitivityarisesfromthefactthatlichenshavenomeansofriddingtheirtissuesofthesesubstances.Itisthoughtthatthepollutantsaccumulateanddestroythechlorophyllinthealgaecells,thusdisruptingtherelationshipwiththefungus.Thisparticularcharacteristicmakeslichensanespeciallygoodindicatorofenvironmentalhealth.Surveyscurrentlyindicatethatlichensarecompletelyabsentfromurbancenterswithpopulationsof100,000ormore.