Wecanbeginourdiscussionof“populationasglobalissue”withwhatmostpersonsmeanwhentheydiscuss“thepopulationproblem”:toomanypeopleonearthandatoorapidincreaseinthenumberaddedeachyear.Thefactsarenotindispute,Itwasquiterighttoemploytheanalogythatlikeneddemographicgrowthto“along,thinpowderfusethatburnssteadilyandhaltinglyuntilitfinallyreachesthechargeandexplodes.”
Tounderstandthecurrentsituation,whichischaracterizedbyrapidincreasesinpopulation,itisnecessarytounderstandthehistoryofpopulationtrends.Rapidgrowthisacomparativelyrecentphenomenon.Lookingbackatthe8,000yearsofdemographichistory,wefindthatpopulationshavebeenvirtuallystableorgrowingveryslightlyformostofhumanhistory.Formostofourancestors,lifewashard,oftennasty,andveryshort.Therewashighfertilityinmostplaces,butthiswasusuallybalancedbyhighmortality.Formostofhumanhistory,itwasseldomthecasethatoneintenpersonswouldlivepastforty,whileinfancyandchildhoodwereespeciallyriskyperiods.Often,societieswereincleardangerofextinctionbecausedeathratescouldexceedtheirbirthrates.Thus,thepopulationproblemthroughoutmostofhistorywashowtopreventextinctionofthehumanrace.
Thispatternisimportanttonotice.Notonlydoesitputthecurrentproblemsofdemographicgrowthintoahistoricalperspective,butitsuggeststhatthecauseofrapidincreaseinpopulationinrecentyearsisnotasuddenenthusiasmformorechildren,butanimprovementintheconditionsthattraditionallyhavecausedhighmortality.
Demographichistorycanbedividedintotwomajorperiods:atimeoflong,slowgrowthwhichextendedfromabout8,000BC.tillapproximatelyAD.1650.Inthefirstperiodofsome9600years,thepopulationincreasedfromsome8millionto500millionin1650.Between1650andthepresent,thepopulationhasincreasedfrom500milliontomorethan4billion.Anditisestimatedthatbytheyear2000therewillbe6.2billionpeoplethroughouttheworld.Onewaytoappreciatethisdramaticdifferenceinsuchabstractnumbersistoreducethetimeframetosomethingthatismoremanageable.Between8000BCand1650,anaverageofonly50,000personswasbeingaddedannuallytotheworld’spopulationeachyear.Atpresent,thisnumberisaddedeverysixhours.Theincreaseisabout80,000,000personsannually.
1.Whichofthefollowingdemographicgrowthpatternismostsuitableforthelongthinpowderfuseanalogy?
A.Avirtuallystableorslightlydecreasingperiodandthenasuddenexplosionofpopulation.
B.Aslowgrowthforalongtimeandthenaperiodofrapid,dramaticincrease.
C.Toomanypeopleonearthandafewrapidincreaseinthenumberaddedeachyear.
D.Alongperiodwhendeathratesexceedsbirthratesandthenashortperiodwithhigherfertilityandlowermortality.
2.Duringthefirstperiodofdemographichistory,societieswereoftenindangerofextinctionbecause___.
A.onlyoneintenpersonscouldlivepast40.
B.therewashighermortalitythanfertilityinmostplaces.
C.itwastoodangeroustohavebabiesduetothepoorconditions.
D.ourancestorshadlittleenthusiasmformorechildren.
3.Whichstatementistrueaboutpopulationincrease?
A.Theremightbeanincreaseof2.2billionpersonsfromnowtotheyear2000.
B.About50,000babiesareborneverysixhoursatpresent.
C.Between8000BCandthepresent,thepopulationincreaseisabout80,000,000personseachyear.
D.Thepopulationincreasedfasterbetween8000BCand1650thanbetween1650andthepresent.
4.Theauthorofthepassageintendsto___.
A.warnpeopleagainstthepopulationexplosioninthenearfuture.
B.comparethedemographicgrowthpatterninthepastwiththatafter1650.
C.findoutthecauseforrapidincreaseinpopulationinrecentyears.
D.presentusaclearandcompletepictureofthedemographicgrowth.
5.Theword“demographic”inthefirstparagraphmeans___.
A.statisticsofhuman.
B.surroundingsstudy.
C.accumulationofhuman.
D.developmentofhuman.
ABADA
暂无解析
InwhatwaydoesLauraLenox-Conynghammakeherliving?
Imeant____youaboutit,butIforgottodoso.
翻译训练：
筷子(chopsticks)是中国传统的独具特色的进食工具(diningutensils)，至今已有数千年的历史。筷子在古代被称为“箸”，大约从明朝开始才有了“筷子”的称呼。筷子多为竹子制成，也有用木头、象牙(ivory)、金属或其他材料制作而成。它要么上方下圆，要么上下全圆而上粗下细。不管其形状如何，筷子必须是成对使用的，并且两只筷子的大小长短要相同。筷子是中国人日常生活的必备工具，它的发明充分反映了中国人民的智慧。
Whyaretoday'soldermiddle-agedandelderlybecomingthenewwinners?
Recentresearchhasclaimedthatanexcessofpositiveionsintheaircanhaveanilleffectonpeople’sphysicalorpsychologicalhealth.Whatarepositiveions?Well,theairisfullofions,electricallychargedparticles,andgenerallythereisaroughbalancebetweenthepositiveandthenegativecharged.Butsometimesthisbalancebecomesdisturbedandalargerproportionofpositiveionsarefound.Thishappensnaturallybeforethunderstorm,earthquakeswhenwindssuchastheMistral,HamsinorSharavareblowingincertaincountries.Oritcanbecausedbyabuild-upofstaticelectricityindoorsfromcarpetsorclothingmadeofman-madefibres,orfromTVsets,duplicatorsorcomputerdisplayscreens.
Whenalargenumberofpositiveionsarepresentintheairmanypeopleexperienceunpleasanteffectssuchasheadaches,fatigue,irritability,andsomesensitivepeoplesuffernauseaorevenmentaldisturbance.Animalsarealsoaffected,particularlybeforeearthquakes,snakeshavebeenobservedtocomeoutofhibernation,ratstofleefromtheirburrows,dogshowlandcatsjumpaboutunaccountably.ThishasledtheUSGeographicalSurveytofundanetworkofvolunteerstowatchanimalsinanefforttoforeseesuchdisastersbeforetheyhitvulnerableareassuchasCalifornia.
Conversely,whenlargenumbersofnegativeionsarepresent,thenpeoplehaveafeelingofwell-being.Naturalconditionsthatproducetheselargeamountsarenearthesea,closetowaterfallsorfountains,orinanyplacewherewaterissprayed,orformsaspray.Thisprobablyaccountsforthebeneficialeffectofaholidaybythesea,orinthemountainswithtumblingstreamsorwaterfalls.
Toincreasethesupplyofnegativeionsindoors,somescientistsrecommendtheuseofionisers:smallportablemachines,whichgeneratenegativeions.Theyclaimthationisersnotonlycleanandrefreshtheairbutalsoimprovethehealthofpeoplesensitivetoexcesspositiveions.Ofcourse,therearethedetractors,otherscientists,whodismisssuchclaimsandareskepticalaboutnegative/positiveionresearch.Thereforepeoplecanonlymakeuptheirownmindsbyobservingtheeffectsonthemselves,oronothers,ofanegativerichorpoorenvironment.Afterallitisdebatablewhetherdependingonseismicreadingstoanticipateearthquakesismoreeffectivethanwatchingthecat.
1.Whateffectdoesexceedingpositiveionizationhaveonsomepeople?
A.Theythinktheyareinsane.
B.Theyfeelratherbad-temperedandshort-fussed.
C.Theybecomeviolentlysick.
D.Theyaretootiredtodoanything.
2.Inaccordancewiththepassage,staticelectricitycanbecausedby___.
A.usinghome-madeelectricalgoods.
B.wearingclothesmadeofnaturalmaterials.
C.walkingonartificialfloorcoverings.
D.copyingTVprogramsonacomputer.
3.Ahighnegativeioncountislikelytobefound___.
A.nearapoundwithawaterpump.
B.closetoaslow-flowingriver.
C.highinsomebarrenmountains.
D.byarotatingwatersprinkler.
4.Whatkindofmachinecangeneratenegativeionsindoors?
A.Ionisers.
B.Air-conditioners.
C.Exhaust-fans
D.Vacuumpumps.
5.Somescientistsbelievethat___.
A.watchinganimalstoanticipateearthquakesismoreeffectivethandependingonseismography.
B.theunusualbehaviorofanimalscannotbetrusted.
C.neitherwatchingnorusingseismographsisreliable.
D.earthquake
