下列关于数据库系统的叙述中,不正确的是 ______。

A、个人计算机系统上的单用户数据库系统一般不支持并发控制
B、分布式系统与非分布式系统的用户操作是完全不同的
C、支持丰富的对象结构和规则是第三代数据库系统的一条准则
D、对象-关系数据库系统中的表已经不再是传统意义上符合第一范式的简单二维表
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正确答案:

B

答案解析:

暂无解析

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Breadandbutter()likedbyWesterners.

A、is
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AccordingtoStevenYoung,ifscientistsgetthedatathat________,theywouldpetitionforfasttrackstatus.

PartIVTranslation

Directions:TranslatethefollowingsentencesintoEnglish.

每个人手里都有一张申请表,但却都不知道送往哪个办公室。

_____himtomorrow.

A、Whynottocallon
B、Whydon'tcallon
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D、Whynotcallon

Passage4

Questions16to20arebasedonthefollowingpassage:

Successfulinnovationshavedrivenmanyoldertechnologiestoextinctionandhaveresultedinhigherproductivity,greaterconsumptionofenergy,increaseddemandofrawmaterials,acceleratedflowofmaterialsthroughtheeconomyandincreasedquantitiesofmetalsandothersubstancesinuseeachperson.Thehistoryofindustrialdevelopmentaboundswithexamples.

In1870,horsesandmulesweretheprimesourceofpoweronU.S.farms.Onehorseormulewasrequiredtosupportfourhumanbeingsaratiothatremainedalmostconstantformanydecades.Atthattime,hadanationalcommissionbeenaskedtoforecastthepopulationfor1970,itsanswerprobablywouldhavedependedonwhetheritsconsultantswereofaneconomicortechnologicalturnofmind.Hadtheybeen“economists”,theywouldprobablyhaveprojectedthe1970horsesormulepopulationtobemorethan50million.Hadtheybeen“technologists”,theywouldhaverecognizedthatthepowerofsteamhadalreadybeenharnessedtoindustryandtolearnandoceantransport.Theywouldhaverecognizedfurtherthatitwouldbetheprimesourceofpoweronthefarm.Itwouldhavebeendifficultforthemtoavoidtheconclusionthatthehorseandmulepopulationwoulddeclinerapidly.

16.Accordingtothepassage,whatsuppliedmostofthepoweronU.S.farmsin1870?

A.AnimalsB.HumansC.EnginesD.Water

17.WhichofthefollowingisNOTmentionedbytheauthorasaconsequenceofnewtechnologicaldevelopments?

A.Oldertechnologiesdieaway.

B.ThequalityoflifeisImproved.

C.Overallproductivityincrease.

D.Morerawmaterialsbecomenecessary.

18.Itcanbeinferredfromthepassagethatby1870.

A.technologybegantobemoreeconomical

B.thesteamenginehadbeeninvented

C.theU.S.horsepopulationwasabout10million

D.anationalcommissionwasabout10million

19.Inthesecondparagraph,theauthorsuggeststhat“economists”would.

A.plantheeconomythroughyearlyforecasts

B.failtoconsidertheinfluenceoftechnologicalinnovation

C.valuetheeconomiccontributionoffarmanimals

D.consultthenationalcommissionontheeconomy

20.Whatistheauthor’sattitudetowardchangesbroughtonbytechnologicalinnovations?

A.Heisexcitedaboutthem.

B.Heacceptthemasnatural.

C.Heisdisturbedbythem.

D.Hequestionstheirusefulness.

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