小编为大家带来评论练习2"，希望对大家GMAT备考有所帮助。

2.Increasesinthelevelofhigh-densitylipoprotein(HDL)inthehumanbloodstreamlowerbloodstreamcholesterollevelsbyincreasingthebody，scapacitytoriditselfofexcesscholestero1.LevelsofHDLinthebloodstreamofsomeindividualsaresignificantlyincreasedbyaprogramofregularexerciseandweightreduction.Whichofthefollowingcanbecorrectlyinferredfromthestatementsabove?

(A)Individualswhoareunderweightdonotrunanyriskofdevelopinghighlevelsofcholesterolinthebloodstream.

(B)Individualswhodonotexerciseregularlyhaveahighriskofdevelopinghighlevelsofcholesterolinthebloodstreamlateinlire.

(C)Exerciseandweightreductionarethemosteffectivemethodsofloweringbloodstreamcholesterollevelsinhumans.

(D)Aprogramofregularexerciseandweightreductionlowerscholesterollevelsinthebloodstreamofsomeindividuals.

(E)Onlyregularexerciseisnecessarytodecreasecholesterollevelsinthebloodstreamofindividualsofaverageweight.

3.Acost—effectivesolutiontotheproblemofairportcongestionistoprovidehigh-speedgroundtransportationbetweenmajorcitieslying200to500milesapart.Thesuccessfulimplementationofthisplanwouldcostfarlessthanexpandingexistingairportsandwouldalsoreducethenumberofairplanescloggingbothairportsandairways.Whichofthefollowing，iftrue，couldproponentsoftheplanabovemostappropriatelyciteasapieceofevidenceforthesoundnessoftheirplan?(A)Aneffectivehigh-speedground--transportationsystemwouldrequiremajorrepairstomanyhighwaysandmass-transitimprovements.(B)One-halfofalldepartingflightsInthenation’sbusiestairportheadforadestinationInamajorcity225milesaway.(C)Themajorityoftravelersdepartingfromruralairportsareflyingtodestinationsincitiesover600milesaway.(D)Manynewairportsarebeingbuiltinareasthatarepresentlyservedbyhigh-speedground-transportationsystems.(E)Alargeproportionofairtravelersarevacationerswhoaretakinglong-distanceflights.

4.Thepricethegovernmentpaysforstandardweaponspurchasedfrommilitarycontractorsisdeterminedbyapricingmethodcalled"historicalcosting"Historicalcostingallowscontractorstoprotecttheirprofitsbyaddingapercentageincrease，basedonthecurrentrateofinflation，tothepreviousyear’scontractualprice.Whichofthefollowingstatements，iftrue，isthebestbasisforacriticismofhistoricalcostingasaneconomicallysoundpricingmethodformilitarycontracts?(A)Thegovernmentmightcontinuetopayforpastinefficientuseoffunds.

(B)Therateofinflationhasvariedconsiderablyoverthepasttwentyyears.(C)Thecontractualpricew-IIbegreatlyaffectedbythecostofmaterialsusedfortheproducts.(D)Manytaxpayersquestiontheamountofmoneythegovernmentspendsonmilitarycontracts.(E)Thepricingmethodbasedonhistoricalcostingmightnotencouragethedevelopmentofinnovativeweapons.

5.Whichofthefollowingbestcompletesthepassagebelow?Establishedcompaniesconcentrateondefendingwhattheyalreadyhave.Consequently,theytendnottobeinnovativethemselvesandtendtounderestimatetheeffectsoftheinnovationsofothers.Theclearestexampleofthisdefensivestrategyisthefactthat.

(A)ballpointpensandsoft-tipmarkershaveeliminatedthetraditionalmarketforfountainpens，clearingthewayforthemarketingoffountainpensasluxuryorprestigeitems(B)ahighlysuccessfulautomobilewasintroducedbythesamecompanythathadearlierintroducedamodelthathadbeenadismalfailure(C)aonce-successfulmanufacturerofsliderulesreactedtotheintroductionofelectroniccalculatorsbytryingtomakebettersliderules(D)oneofthefirstmodelsofmodernaccountingmachines，designedforuseinthebankingindustry,waspurchasedbyapubliclibraryaswellasbybanks(E)theInventor0facommonlyusedanestheticdidnotintendtheproducttobeusedbydentists，whocurrentlyaccountforalmosttheentiremarketforthatdrug

6.Sincethemayor’spublicitycampaignforGreenville’sbusservicebegansixmonthsago.morningautomobiletrafficintothemidtownareaofthecityhasdecreasedsevenpercent.Duringthesameperiod，therehasbeenanequivalentriseinthenumberofpersonsridingbusesintothemidtownarea.Obviously,themayor’spublicitycampaignhasconvincedmanypeopletoleavetheircarsathomeandridethebustowork.Whichofthefollowing，iftrue，caststhemostseriousdoubtontheconclusiondrawnabove?