2011年大学英语六级阅读理解107篇本文由dddsssrq贡献1 We can begin our discussion of "population as global issue"with what most personsmean when they discuss "the population problem":too many people on earth and a toorapid increase in the number added each year.The facts are not in dispute,It was quiteright to employ the analogy that likened demographic growth to "a long,thin powderfuse that burns steadily and haltingly until it finally reaches the charge and explodes.To understand the current situation,which is characterized by rapid increases inpopulation,it is necessary to understand the history of population trends.Rapid growthis a comparatively recent phenomenon.Looking back at the 8,000 years of demographichistory,we find that populations have been virtually stable or growing very slightlyfor most of human history.For most of our ancestors,life was hard,often nasty,andvery short.There was high fertility in most places,but this was usually balanced byhigh mortality.For most of human history,it was seldom the case that one in ten personswould live past forty,while infancy and childhood were especially risky periods.Often,societies were in clear danger of extinction because death rates could exceed theirbirthrates.Thus,the population problem throughout most of history was how to preventextinction of the human race.This pattern is important to notice.Not only does itput the current problems of demographic growth into a historical perspective,but itsuggests that the cause of rapid increase in population in recent years is not a suddenenthusiasm for more children,but an improvement in the conditions that traditionallyhave caused high mortality.Demographic history can be divided into two major periods:a time of long,slow growth which extended from about 8,000 BC.till approximately AD.1650.In the first period of some 9600 years,the population increased from some 8million to 500 million in 1650.Between 1650 and the present,the population hasincreased from 500 million to more than 4 billion.And it is estimated that by the year2000 there will be 6.2 billion people throughout the world.One way to appreciate thisdramatic difference in such abstract numbers is to reduce the time frame to somethingthat is more manageable.Between 8000BC and 1650,an average of only 50,000 personswas being added annually to the world's population each year.At present,this numberis added every six hours.The increase is about 80,000,000 persons annually.1.Whichof the following demographic growth pattern is most suitable for the long thin powderfuse analogy?A.A virtually stable or slightly decreasing period and then a suddenexplosion of population.B.A slow growth for a long time and then a period of rapid,dramatic increase.C.Too many people on earth and a few rapid increase in the numberadded each year.D.A long period when death rates exceeds birthrates and then a shortperiod with higher fertility and lower mortality.2.During the firstperiod of demographic history,societies were often in danger of extinction because_A.only one in ten persons could live past 40.B.there was higher mortality than fertilityin most places.C.it was too dangerous to have babies due to the poor conditions.D.ourancestors had little enthusiasm for more children.3.Which statement is true aboutpopulation increase?A.There might be an increase of 2.2 billion persons from now tothe year 2000.:ABADA B.About 50,000 babies are born every six hours at present.C.Between 8000 BC and the present,the population increase is about 80,000,000 personseach year.D.The population increased faster between 8000BC and 1650 than between 1650and the present.4.The author of the passage intends to.A.warn people against thepopulation explosion in the near future.B.compare the demographic growth pattern inthe past with that after 1650.C.find out the cause for rapid increase in populationin recent years.D.present us a clear and complete picture of the demographic growth.5.The word "demographic"in the first paragraph means.A.statistics of human.B.surroundings study.C.accumulation of human.D.development of human.2 Most of us are taught to pay attention to what is said-the words.Words do provideus with some information,but meanings are derived from so many other sources that itwould hinder our effectiveness as a partner to a relationship to rely too heavily onwords alone.Words are used to describe only a small part of the many ideas we associatewith any given message.Sometimes we can gain insight into some of those associationsif we listen for more than words.We don't always say what we mean or mean what wesay.Sometimes our words don't mean anything except "I'm letting off some steam.I don't really want you to pay close attention to what I'm saying.Just pay attentionto what I'm feeling.Mostly we mean several things at once.A person wanting to purchasea house says to the current owner,"This step has to be fixed before I'11 buy.Theowner says,It's been like that for years.Actually,the step hasn't been likethat for years,but the unspoken message is:I don't want to fix it.We put up withit.Why can't you?"The search for a more expansive view of meaning can be developedof examining a message in terms of who said it,when it occurred,the related conditionsor situation,and how it was said.When a message occurs can also reveal associated meaning.Let us assume two couplesdo exactly the same amount of kissing and arguing.But one couple always kisses afteran argument and the other couple always argues after a kiss.The ordering of thebehaviors may mean a great deal more than the frequency of the behavior.A friend's unusually docile behavior may only be understood by noting that it was preceded bysituations that required an abnormal amount of assertiveness.Some responses may bedirectly linked to a developing pattern of responses and defy logic.For example,a person who says "No!"toa serials of charges like“You're dumb,”“You're lazy,”and“You're dishonest,”may also say "No!"and try to justify his or her response if the next statement is"And you're good looking.We would do well to listen for how messages are presented.The words,"If sure has been nice to have you over,can be said with emphasis andexcitement or ritualistically.The phrase can be said once or repeated several times.And the meanings we associate with the phrase will change accordingly.Sometimes ifwe say something infrequently it assumes more importance:sometimes the more we saysomething the less importance it assumes.1.Effective communication is renderedpossible between two conversing partners,if.A.they use proper words to carry theirideas.B.they both speak truly of their own feelings.C.they try to understand eachother's ideas beyond words.D.they are capable of associating meaning with their words.2."I'm letting off some steam"in paragraph 1 means_.A.I'm just calling yourattention.B.I'm just kidding.C.I'm just saying the opposite.D.I'm just givingoff some sound.3.The house-owner's example shows that he actually means_.A.thestep has been like that for years.B.he doesn't think it necessary to fix the step.DBABC C.the condition of the step is only a minor fault.D.the cost involved inthe fixing should be shared.4.Some responses and behaviors may appear very illogical,but are justifiable if.A.linked to an abnormal amount of assertiveness.B.seen asone's habitual pattern of behavior.C.taken as part of an ordering sequence.D.expressedto a series of charges.5.The word "ritualistically"in the last paragraph equalssomething done_.A.without true intention.B.light-heartedly.C.in a way of ceremony.D.with less emphasis.3 A controversy erupted in the scientific community in early 1998 over the use of DNA(deoxyribonucleic acid)fingerprinting in criminal investigations.DNA fingerprintingwas introduced in 1987 as a method to identify individuals based on a pattern seen intheir DNA,the molecule of which genes are made.DNA is present in every cell of thebody except red blood cells.DNA fingerprinting has been used successfully in variousways,such as to determine paternity where it is not clear who the father of a particularchild is.However,it is in the area of criminal investigations that DNA fingerprintinghas potentially powerful and controversial uses.DNA fingerprinting and other DNAanalysis techniques have revolutionized criminal investigations by givinginvestigators powerful new tools in the attempt to trove guilt,not just establishinnocence.When used in criminal investigations,a DNA fingerprint pattern from asuspect is compared with a DNA fingerprint pattern obtained from such material as hairsor blood found at the scene of a crimeA match between the two DNA samples can be used as evidence to convict a suspect.The controversy in 1998 stemmed form a report published in December 1991 by populationgeneticists Richard C.Lewontin of Harvard University in Cambridge,Mass.,and DanielL.Hartl called into question the methods to calculate how likely it is that a matchbetween two DNA fingerprints might occur by chance alone.In particular,they arguedthat the current method cannot properly determine the likelihood that two DNA sampleswill match because they came from the same individual rather than simply from twodifferent individuals who are members of the same ethnic group.Lewontin and Hartlcalled for better surveys of DNA patterns methods are adequate.In response to theircriticisms,population geneticists Ranajit Chakraborty of the University of Texas inDallas and Kenneth K.Kidd of Yale University in New Haven,Conn.,argued that enoughdata are already available to show that the methods currently being used are adequate.In January 1998,however,the federal Bureau of Investigation and laboratories thatconduct DNA tests announced that they would collect additional DNA samples form variousethnic groups in an attempt to resolve some of these questions.And,in April,a NationalAcademy of Sciences called for strict standards and system of accreditation for DNAtesting laboratories.1.Before DNA fingerprinting is used,suspects_.A.would haveto leave their fingerprints for further investigations B.would have to submit evidencefor their innocence C.could easily escape conviction of guilt D.cold be convicted ofguilt as well2.DNA fingerprinting can be unreliable whenA.the methods used for blood-cellcalculation are not accurate B.two different individuals of the same ethnic group mayhave the same DNA fingerprinting patternC.a match is by chance left with fingerprints that happen to belong to two differentindividuals D.two different individuals leave two DNA samples.3.To geneticists like