关系模型把各种关系都统一描述为一些________。

A、记录
B、字段
C、二维表
D、属性
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正确答案:

C

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Youngpeoplewhocommitseriouscrimesshouldbepunishedinthesamewayasadults.Towhatextentdoyouagreeordisagree?

1.Thefailureofahigh-profilecholesteroldrughasthrownaspotlightonthecomplicatedmachinerythatregulatescholesterollevels.Butmanyresearchersremainconfidentthatdrugstoboostlevelsof'good'cholesterolarestilloneofthemostpromisingmeanstocombatspirallingheartdisease.

2.DrugcompanyPfizerannouncedon2Decemberthatitwascancellingallclinicaltrialsoftorcetrapib,adrugdesignedtoraiseheart-protectivehigh-densitylipoproteins(HDLs).Inatrialof15000patients,asafetyboardfoundthatmorepeoplediedorsufferedcardiovascularproblemsaftertakingthedrugplusacholesterol-loweringstatinthanthoseinacontrolgroupwhotookthestatinalone.

3.Thenewscameasakickintheteethtomanycardiologistsbecauseearliertestsinanimalsandpeoplesuggesteditwouldlowerratesofcardiovasculardisease."Therehavebeennoredflagstomyknowledge,"saysJohnChapman,aspecialistinlipoproteinsandatherosclerosisattheNationalInstituteforHealthandMedicalResearch(INSERM)inPariswhohasalsostudiedtorcetrapib."Thiscancellationcameasacompleteshock."

4.TorcetrapibisoneofthemostadvancedofanewbreedofdrugsdesignedtoraiselevelsofHDLs,whichferrycholesteroloutofartery-cloggingplaquestotheliverforremovalfromthebody.Specifically,torcetrapibblocksaproteincalledcholesterolestertransferprotein(CETP),whichnormallytransfersthecholesterolfromhigh-densitylipoproteinstolowdensity,plaque-promotingones.Statins,incontrast,mainlyworkbyloweringthe'bad'low-densitylipoproteins.

Underpressure

5.Researchersarenowtryingtoworkoutwhyandhowthedrugbackfired,somethingthatwillnotbecomeclearuntiltheclinicaldetailsarereleasedbyPfizer.Onehintliesinevidencefromearliertrialsthatitslightlyraisesbloodpressureinsomepatients.Itwasthoughtthatthismildproblemwouldbeoffsetbytheheartbenefitsofthedrug.Butitispossiblethatitactuallyprovedfatalinsomepatientswhoalreadysufferedhighbloodpressure.Ifbloodpressureistheexplanation,itwouldactuallybegoodnewsfordrugdevelopersbecauseitsuggeststhattheproblemsarespecifictothiscompound.OtherprototypedrugsthatarebeingdevelopedtoblockCETPworkinaslightlydifferentwayandmightnotsufferthesamedownfall.

6.ButitisalsopossiblethatthewholeideaofblockingCETPisflawed,saysMotiKashyap,whodirectsatherosclerosisresearchattheVAMedicalCenterinLongBeach,California.WhenHDLsexcretecholesterolintheliver,theyactuallyrelyonLDLsforpartofthisprocess.SoinhibitingCETP,whichpreventsthetransferofcholesterolfromHDLtoLDL,mightactuallycauseanabnormalandirreversibleaccumulationofcholesterolinthebody."You'reblockingaphysiologicmechanismtoeliminatecholesterolandeffectivelyconstipatingthepathway,"saysKashyap.Goingup

7.Mostresearchersremainconfidentthatelevatinghighdensitylipoproteinslevelsbyonemeansoranotherisoneofthebestroutesforhelpingheartdiseasepatients.ButHDLsarecomplexandnotentirelyunderstood.Oneapproveddrug,calledniacin,isknowntobothraiseHDLandreducecardiovascularriskbutalsocausesanunpleasantsensationofheatandtingling.Researchersareexploringwhethertheycanbypassthissideeffectandwhetherniacincanlowerdiseaseriskmorethanstatinsalone.Scientistsarealsoworkingonseveralothermeanstobumpuphigh-densitylipoproteinsby,forexample,introducingsyntheticHDLs."Theonlythingweknowisdeadinthewateristorcetrapib,notthewholeideaofraisingHDL,"saysMichaelMiller,directorofpreventivecardiologyattheUniversityofMarylandMedicalCenter,Baltimore.

Questions7-13

Matchtorcetrapib,HDLs,statinandCETPwiththeirfunctions(Questions8-13)..WritethecorrectletterA,B,CorDinboxes8-13onyouranswersheet.NBYoumayuseanylettermorethanonce.

7.Ithasbeenadministeredtoover10,000subjectsinaclinicaltrial.

8.Itcouldhelpridhumanbodyofcholesterol.

9.Researchersareyettofindmoreaboutit.

10.Itwasusedtoreducethelevelofcholesterol.

11.AccordingtoKashyap,itmightleadtounwantedresultifit'sblocked.

12.Itproducedcontradictoryresultsindifferenttrials.

13.ItcouldinhibitLDLs.Listofchoices

A.TorcetrapicB.HDLSC.StatinD.CETP

人类活动已经对生态系统造成严重破坏。

Whatisagenerallyacknowledgedasthemostpowerfuladvertisingmediumandreachesabroadspectrumofconsumers.()

A、radioads
B、printads
C、televisionads
D、magazinesads

Whatisnotthemeetinglayout?

A、theatrestyle
B、Classroomstyle
C、ovalstyle
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