Whileintegrasedeletesanimmunecell'sgeneticmaterialandreplacesitwithitsown,itactslike________inawordprocessor.

查看答案
正确答案:

a cut and paste operation

答案解析:

暂无解析

上一题
你可能感兴趣的试题

Onceitwaspossibletodefinemaleandfemaleroleseasilybythedivisionoflabor.Menworkedoutsidethehomeandearnedtheincometosupporttheirfamilies,whilewomencookedthemealsandtookcareofthehomeandthechildren.Theseroleswerefirmlyfixedformostpeople,andtherewasnotmuchopportunityforwomentoexchangetheirroles.Butbythemiddleofthiscentury,men’sandwomen’sroleswerebecominglessfirmlyfixed.

Inthe1950s,economicandsocialsuccesswasthegoalofthetypicalAmerican.Butinthe1960sanewforcedevelopedcalledthecounterculture.Thepeopleinvolvedinthismovementdidnotvaluethemiddle-classAmericangoals.Thecounterculturepresentedmenandwomenwithnewrolechoices.Takingmoreinterestinchildcare,menbegantosharechild-raisingtaskswiththeirwives.Infact,someyoungmenandwomenmovedtocommunalhomesorfarmswheretheeconomicandchildcareresponsibilitiesweresharedequallybybothsexes.Inaddition,manyAmericansdidnotvaluethetraditionalmaleroleofsoldier.SomeyoungmenrefusedtobedraftedassoldierstofightinthewarinVietnam.

Intermsofnumbers,thecounterculturewasnotaverylargegroupofpeople.ButitsinfluencespreadtomanypartsofAmericansociety.Workingmenofallclassesbegantochangetheireconomicandsocialpatterns.Industrialworkersandbusinessexecutivesalikecutdownon“overtime”worksothattheycouldspendmoreleisuretimewiththeirfamilies.Somedoctors,lawyers,andteachersturnedawayfromhighpayingsituationstopracticetheirprofessionsinpoorerneighborhoods.

Inthe1970s,thefeministmovement,orwomen’sliberation,producedadditionaleconomicandsocialchanges.Womenofallagesandatalllevelsofsocietywereenteringtheworkforceingreaternumbers.Mostofthemstilltooktraditionalwomen’sjobsaspublicschoolteaching,nursing,andsecretarialwork.Butsomewomenbegantoentertraditionallymaleoccupations:policework,banking,dentistry,andconstructionwork.Womenwereaskingforequalwork,andequalopportunitiesforpromotion.

Todaytheexpertsgenerallyagreethatimportantchangesaretakingplaceintherolesofmenandwomen.Naturally,therearedifficultiesinadjustingtothesetransformations.

1.WhichofthefollowingbestexpressthemainideaofParagraph1?

A.Womenusuallyworkedoutsidethehomeforwages.

B.Menandwomen’sroleswereeasilyexchangedinthepast.

C.Men’srolesathomeweremorefirmlyfixedthanwomen’s.

D.Menandwomen’sroleswereusuallyquiteseparatedinthepast.

2.WhichsentencebestexpressesthemainideaofParagraph2?

A.Thefirstsentence.

B.Thesecondandthethirdsentences.

C.Thefourthsentence.

D.Thelastsentence.

3.Inthepassagetheauthorproposesthatthecounterculture___.

A.destroyedtheUnitedStates.

B.transformedsomeAmericanvalues.

C.wasnotimportantintheUnitedStates.

D.broughtpeoplemoreleisuretimewiththeirfamilies.

4.Itcouldbeinferredfromthepassagethat___.

A.menandwomenwillneversharethesamegoals.

B.somemenwillbewillingtoexchangetheirtraditionalmaleroles.

C.mostmenwillbehappytosharesomeofthehouseholdresponsibilitieswiththeirwives.

D.moreAmericanhouseholdsareheadedbywomenthaneverbefore.

5.Thebesttitleforthepassagemaybe___.

A.ResultsofFeministMovements

B.NewinfluenceinAmericanLife

C.CountercultureandItsconsequence

D.TraditionalDivisionofMaleandFemaleRoles.

Lifeistooshort________________(不可每天将时间浪费在看电视上).

Weareconvinced____therighteousnessofourcause.

A、of
B、on
C、over
D、at

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.

Whyaretoday'soldermiddle-agedandelderlybecomingthenewwinners?

A、Becausetheymaderelativelysmallcontributionsintax,butyoungergenerationwillpossiblyhandovermorethanathirdoftheirlifetime'searningsforthecareofthem
B、Becausetheycontributedalotintaxandnowcanclaimmuchonthewelfaresystem
C、Becausetheymadesmallcontributions,butnowcanmakemoneyeasily
D、Becausetheyoutnumberyoungergenerationandenjoymoreprivilegesinthepresentsociety
热门试题 更多>
相关题库更多>
大学英语四级
大学英语六级
大学英语三级
试卷库
试题库