三氧化硫极易吸水,在空气中强烈发烟;溶于水形成硫酸,溶于浓硫酸形成发烟硫酸,并产生大量溶解热。
更新时间:2024-10-30 03:27:11正确
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There_____nothingmorefordiscussion,themeetingcametoanendhalfanearlier.
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.
翻译训练:普通话与方言
中国土地广阔,人口众多。尽管全国都讲汉语,但是不同地区的人说汉语的方式不同,这被称为方言。方言一般被称为地方话,是汉语在不同地区的分支,只在特定地区使用。汉语方言非常复杂。它们有以下三方面不同:发音、词汇和语法。发音的区别最为显著。2000多年前,中国人发现社交时应该使用统一的语言。和方言相比,普通话(mandarin)能被所有人理解。普通话有利于不同种族、地区人民之间的信息传递和文化交流。
Evenifhisletter()tomorrow,it()toolatetodoanything.
PARTVREADINGCOMPREHENSION
Inthissectiontherearefourpassagesfollowedbyquestionsorunfinishedstatements,eachwithfoursuggestedanswersmarkedA,B,CandD.Choosetheonethatyouthinkisthebestanswer.
TEXTA
Racket,dinclamor,noise,whateveryouwanttocallit,unwantedsoundisAmerica'smostwidespread
nuisance.Butnoiseismorethanjustanuisance.Itconstitutesarealandpresentdangertopeople'shealth.Day
andnight,athome,atwork,andatplay,noisecanproduceseriousphysicalandpsychologicalstress.Nooneis
immunetothisstress.Thoughweseemtoadjusttonoisebyignoringit,theear,infact,neverclosesandthe
bodystillresponds—sometimeswithextremetension,astoastrangesoundinthenight.
Theannoyancewefeelwhenfacedwithnoiseisthemostcommonoutwardsymptomofthestressbuilding
upinsideus.Indeed,becauseirritabilityissoapparent,legislatorshavemadepublicannoyancethebasisof
manynoiseabatementprograms.Themoresubtleandmoreserioushealthhazardsassociatedwithstress
causedbynoisetraditionallyhavebeengivenmuchlessattention.Nevertheless,whenweareannoyedormade
irritablebynoise,weshouldconsiderthesesymptomsfairwarningthatotherthingmaybehappeningtous,
someofwhichmaybedamagingtoourhealth.
Ofmanyhealthhazardstonoise,hearinglossisthemostclearlyobservableandmeasurablebyhealth
professionals.Theotherhazardsarehardertopindown.Formanyofus,theremaybeariskthatexposuretothe
stressofnoiseincreasessusceptibilitytodiseaseandinfection.Themoresusceptibleamongusmayexperience
noiseasacomplicatingfactorinheartproblemsandotherdiseases.Noisethatcausesannoyanceandirritability
inhealthpersonsmayhaveseriousconsequencesforthesealreadyillinmindorbody.
Noiseaffectsusthroughoutourlives.Forexample,thereareindicationsofeffectsontheunbornchildwhen
mothersareexposedtoindustrialandenvironmentalnoise.Duringinfancyandchildhood,youngstersexposed
tohighnoiselevelsmayhavetroublefallingasleepandobtainingnecessaryamountsofrest.
Why,then,istherenotgreateralarmaboutthesedangers?Perhapsitisbecausethelinkbetweennoiseand
manydisabilitiesordiseaseshasnotyetbeenconclusivelydemonstrated.Perhapsitisbecausewetendto
dismissannoyanceasapricetopayforlivinginthemodernworld.Itmayalsobebecausewestillthinkof
hearinglossasonlyanoccupationalhazard.
1.InParagraph1,thephrase"immuneto"areusedtomean___.
A.unaffectedby
B.hurtby
C.unlikelytobeseenby
D.unknownby
2.Theauthor'sattitudetowardnoisewouldbestbedescribedas___.
A.unrealistic
B.traditional
C.concerned
D.hysterical
3.Whichofthefollowingbeststatesthemainideaofthepassage?
A.Noiseisamajorproblem;mostpeoplerecognizeitsimportance.
B.Althoughnoisecanbeannoying,itisnotamajorproblem.
C.Noiseisamajorproblemandhasnotyetbeenrecognizedassuch.
D.Noiseisamajorproblemaboutwhichnothingcanbedone.
4.Theauthorcondemnsnoiseessentiallybecauseit___.
A.isagainstthelaw
B.canmakesomepeopleirritable
C.isanuisance
D.inagangertopeople'shealth
5.Theauthorwouldprobablyconsiderresearchabouttheeffectsnoisehasonpeopletobe___.
A.unimportant
B.impossible.
C.awasteofmoney
D.essential