单选题1 Animal behaviorists believe the orangutan is a cultured ape, able to learn new living habits and to pass them along to the next generation. Some orangutan parents teach their young to use leaves as napkins, while others demonstrate the technique of getting water from a hole by dipping a branch in and then licking the leaves. Orangutans have been observed saying goodnight with the gift of a juicy raspberry. Such social interactions lead researchers to conclude that if orangutans have culture, then the capacity to learn culture is very ancient. 2 In the evolutionary timeline, orangutans separated from the ancestors of humans many millions of years ago, and they may have had culture before they separated. The discovery of orangutan culture suggests that early primates--including ancestors of humans--might have developed the ability to invent new behaviors, such as tool use, as early as 14 million years ago, approximately 6 million years earlier than once believed.
单选题(Researchers) have found subtle neurological (differences) between the brains of men and women (either) in physical structure and in (the way) they function.
单选题(Due to) persistent inbreeding, self-pollinating plants (have) genetically more uniform than cross-pollinated plants,(which) harbor more genetic (variability).
单选题Ruth Bader Ginsburg argued six women's rights cases before the United States Supreme Court in the 1970's,____
单选题NorthAmericanGrasslandsInNorthAmerica,nativegrasslandsoccurprimarilyintheGreatPlainsinthemiddleofthecontinent.TheNorthAmericanprairiebiomeisoneofthemostextensivegrasslandsintheworld,extendingfromtheedgeoftheRockyMountainsinthewesttothedeciduousforestintheeast,andfromnorthernMexicointhesouthtoCanadainthenorth.Averageannualrainfallrangesfromabout40cm(16inches)inthewestto80cm(31inches)intheeast.Averageannualtemperaturesrangebetween10degreesand20degreesCelsius(50to68degreesFahrenheit).InthemoistregionsoftheNorthAmericangrasslands,especiallyinthenorthernGreatPlains,rainfallisdistinctlyseasonal,andtemperaturescanvarywidelyfromveryhotinsummertobittercoldinwinter.Onehundredyearsago,theGreatPlainsgrasslandswereonevast,unbrokenprairie.Muchoftheprairieisnowfarmland,themostproductiveagriculturalregionintheworld,dominatedbymonoculturesofcerealgrains.Wheat,barley,soybeans,corn,andsunflowersoccupythelandthatwasonceprairie.Inareasgivenovertograzinglandsforcattleandsheep,virtuallyallthemajornativegrasseshavebeenreplacedbyalienspecies.AnimportantfeatureofthenorthernGreatPlainsgrasslandsisthepresenceofmillionsofglacialdepressionsthatarenowsmallpondsknownasprairiepotholes.TheywereformedduringthemostrecentIceAge,whenstreamsflowedintunnelsbeneathglaciallyformedsandyridges.WhentheIceAgeendedaround12,000yearsago,theretreatingglacierscreatedabout25milliondepressionsacrossa300,000-square-milelandscape--about83potholespersquaremile.Astheiceblocksmelted,muchofthewaterwasleftbehind,formingwetlandsranginginsizefromatenthofanacretoseveralacres.Thewetlandsweresoonsurroundedbyflutteringwavesofgrasses:shortgrass,mixedgrass,andtallgrass.Todaythesesmallwetlandsstillcovertheprairies,althoughmuchofthelandscapeincludingbothnativegrassesandpotholeshasbeentransformedtocroplandandgrasslandforgrazing.Whatdoesremainofthewetlands,however,stillservesasanimportantbreedingareaformorethan300birdspecies,includinglargenumbersofmigratingshorebirdsandwaterfowl.Thepotholesfillupwithwaterduringspringrainsandusuallydryoutbylatesummer.Everyspring,birdsarriveingreatnumbers--northernpintails,mallards,coots,andpied-billedgrebes--4to6millionstrong,tomateintheseasonalwetlandsthatdotportionsofMinnesota,Iowa,NorthandSouthDakota,Montana,Alberta,Saskatchewan,andManitoba.PrairiepotholecountryproduceshalfofNorthAmerica's35to40millionducksandisrenownedworldwideasa"duckfactory".Recentlybiologistshavediscoveredthattheprairiepotholeregionispotentiallyavastcarbonsink:anaturalspongethatabsorbscarbondioxideemissionsfromcars,factories,andpowerplants.Carbondioxideisthemostcommonofallthepollutantsactingasgreenhousegasesthatheatuptheatmosphere.Fortunately,however,carbondioxideiscapturednaturallyandstoredintrees,soil,andplants.Scientistshavetermedthis"carbonsequestration".Theyhavedeterminedthatprairiepotholesholdanaverageof2.5tonsofcarbonperacreperyearwhennotbeingfarmed.ThismeansthatiftheentirepotholeregionintheUnitedStatesandCanadaweretostopbeingfarmed,theregionwouldstoreabout400milliontonsofcarbonover10years--theequivalentoftakingalmost4millioncarsofftheroad.Thus,preservingthepotholescouldbeawaytooffsetgreenhousegasemissionsthatarewarmingtheplanet.Glossary:biome:oneoftheworld'smajornaturalcommunities,classifiedbypredominantvegetationmonoculture:cultivationoflargelandareaswithasingleplantvariety
单选题Some of sharpshooter Annie Oakley’s exploits with a gun are almost unbelievable when it comes to accuracy, speed of firing,and endure.
单选题Made of hard wood, the boomerang is roughly V-shaped, with arms — skewed
单选题Most geologists believe — from the remains of tiny marine plants and animals that died millions of years ago.
单选题Hydrofoils can exceed 75 miles per hour, as compared with conventional watercraft, whose maximum speeds .......... approach 50 miles per hour.
单选题The bathyscaphe, a free-moving vessel designed for underwater exploration, consists of a Flotation compartment with a observation capsule attached underneath it.
单选题Listening2"LiteratureClass"
单选题1 Erik Erikson believed that personality development is a series of turning points, which he described in terms of the tension between desirable qualities and dangers. He emphasized that only when the positive qualities outweigh the dangers does healthy psychosocial development take place. 2 An important turning point occurs around age six. A child entering school is at a point in development when behavior is dominated by intellectual curiosity and performance. He or she now learns to win recognition by producing things. The child develops a sense of industry. The danger at this stage is that the child may experience feelings of inadequacy or inferiority. If the child is encouraged to make and do things, allowed to finish tasks, and praised for trying, a sense of industry is the result. On the other hand, if the child's efforts are unsuccessful, or if they are criticized or treated as bothersome, a sense of inferiority is the result. For these reasons, Erikson called the period from age six to eleven Industry vs. Inferiority.
单选题Listening6"HistoryClass"
单选题Although most petroleum is produced from underground reservoirs, petroleum occurs in a varieties of forms at the surface
单选题Connecticut was the fifth of the original thirteen states ........ the Constitution of the United States.
单选题Listentopartofaconversationbetweenapart-timestudentandthemanageroftheschoolcafeteria.Nowgetreadytoanswerthequestions.Youmayuseyournotestohelpyouanswer.
单选题The round, hard-shelled nuts of the macadamia tree grow in clusters and are covered with husks what split when the nuts are ripe
单选题Mr. Hui, a freelance writer here at ESS Newspapers, has impeccable
for the position of senior editor.
单选题
单选题Why does the author mention "aragonite" in line 26