GRE试题二(2)

10.Aworldwidebanontheproductionofcertainozone-destroyingchemicalswouldprovideonlyanillusionofprotection.Quantitiesofsuchchemicals,alreadyproduced,existascoolantsinmillionsofrefrigerators.Whentheyreachtheozonelayerintheatmosphere,theiractioncannotbehalted.Sothereisnowaytopreventthesechemicalsfromdamagingtheozonelayerfurther.

Whichofthefollowing,iftrue,mostseriouslyweakenstheargumentabove?

(A)Itisimpossibletomeasurewithaccuracythequantityofozone-destroyingchemicalsthatexistascoolantsinrefrigerators.(B)Inmodernsocieties,refrigerationoffoodisnecessarytopreventunhealthyandpotentiallylife-threateningconditions.(C)Replacementchemicalsthatwillnotdestroyozonehavenotyetbeendevelopedandwouldbemoreexpensivethanthechemicalsnowusedascoolantsinrefrigerators.(D)Evenifpeopleshouldgiveuptheuseofrefrigeration,thecoolantsalreadyinexistingrefrigeratorsareathreattoatmosphericozone.(E)Thecoolantsinrefrigeratorcanbefullyrecoveredattheendoftheusefullifeoftherefrigeratorsandreused.

Question11--15

Agovernmentisassigningeachofsixembassyofficeworkers--Farr,Golden,Hayakawa,Inserra,Jones,andKovacs--toembassies.Therearefourembassies.EmbassiesLandMarelocatedincountrieswithdryclimates,whereasembassiesPandTarelocatedincountrieswithhumidclimates.Theofficeworkersmustbeassignedaccordingtothefollowingrules:

Eachembassymusthaveatleastoneoftheworkersassignedtoit.Atleastoneembassyinahumidclimatemusthaveatleasttwoworkersassigned

toit.GoldencannotbeassignedtothesameembassyasKovacs.Inserramustbeassignedtanembassyinadryclimates.Jonesmustbeassignedtoanembassyinahumidclimate.11.Whichofthefollowingisanacceptableassignmentoftheworkerstotheembassies?

LMPT(A)Farr,GoldenInserra,KovacsHayakawaJones(B)Golden,KovacsInserraJonesFarr,Hayakawa(C)GoldenFarr,InserraKovacsJones,Hayakawa(D)JonesGolden,InserraHayakawaFarr,Kovacs(E)KovacsFarr,HayakawaInserraGolden,Jones

12.WhichofthefollowingmustbeassignedeithertoembassyLortoembassyM?

(A)Farr(B)Golden(C)Hayakawa(D)Inserra(E)Kovacs

13.WhichofthefollowingCANNOTbetrue?

(A)OneworkerisassignedtoL.(B)TwoworkersisassignedtoP.(C)TwoworkersareassignedtoL.(D)ThreeworkersareassignedtoM.(E)ThreeworkersareassignedtoT.

14.IfGoldenandKovacsareassignedtoLandM,respectively,whichofthefollowingmustbetrue?

(A)FarrisassignedtoeitherPorT.(B)InserraisassignedtoeitherPorT.(C)PandTeachhavetwoworkersassignedtothem.(D)HayakawaisassignedtoL.(E)HayakawaisassignedtoT.

15.IfGolden,Hayakawa,andKovacsareamongtheworkersassignedtoembassiesinhumidclimayes,whichofthefollowingmustbetrue?

(A)Farrisassignedtoanembassytowhichnoneoftheotherfiveofficeworkersisassigned.(B)Goldenisassignedtoanembassytowhichnoneoftheotherfiveofficeworkersisassigned.(C)JonesisassignedtothesameembassyasGolden.(D)HayakawaisassignedtothesameembassyasGolden.(E)HayakawaisassignedtothesameembassyasKovacs.

Question16--19

Avolunteerusesatrucktopickupdonationsofunsoldfoodandclothingfromstoresandtodeliverthemtolocationswheretheycanbedistributed.Hedrivesonlyalongacertainnetworkofroads.

Inthenetworktherearetwo-wayroadsconnectingeachofthefollowingpairsofpoints:1with2,1with3,1with5,2with6,3with7,5with6,and6with7.Therearealsoone-wayroadsgoingfrom2to4,from3to2,andfrom4to3.Therearenootherroadsinthenetwork,andtheroadsinthenetworkdonotintersect.

Tomakeatripinvolvingpickupsanddeliverirs,thevolunteeralwaystakesaroutethatforthewholetrippassesthroughthefewestofthepoints1through7,countingapointtwiceifthevolunteerpassesthroughittwice.

Thevolunteer’shomeisatpoint3.Donationscanbepickedupatasupermarketatpoint1,aclothingstoreatpoint5,andabakeryatpoint4.Deliveriescanbemadeasneededtoatutoringcenteratpoint2,adistributioncenteratpoint6,andashelteratpoint7.

16.Ifthevolunteerstartsatthesupermarketandnextistogototheshelter,thefirstintermediatepointhisrputepassesthroughmustbe

(A)2(B)3(C)5(D)6(E)7

17.If,startingfromhome,thevolunteernextistomakepickupsfortheshelteratthesupermarketandthebakery(ineitherorder),thefirsttwointermediatepointsonhisroute,beginningwiththefirst,mustbe

(A)1and2(B)1and3(C)2and1(D)2and4(E)4and2

18.If,startingfromtheclothingstore,thevolunteernextistopickupbreadateitherthesupermarketorthebakery(whicheverstopmakeshisroutegothroughthefewestofthepoints)andthenistogototheshelter,thefirsttwopointshereachesaftertheclothingstore,beginningwiththefirst,mustbe

(A)1and2(B)1and3(C)4and2(D)6and2(E)6and4

19.Ifthevolunteeristomakeatripstartingattheshelter,nextgoingtothebakeryforapickup,andthenendingatthedistributioncenter,thefirsttwointermediatepointsonhisroute,beginningwiththefirst,canbe

(A)3and1(B)3and4(C)4and2(D)6and2(E)6and5

Question20--22

Adeveloperisplanningtobuildahousingcomplexonanemptytractofland.Exactlysevendifferentstylesofhouses--Q,R,S,T,W,X,andZ--willbebuildinthecomplex.Thecomplexwillcontainseveralblocks,andthedeveloperplanstoputhousesofatleastthreedifferentstylesoneachblock.Thedeveloperwillbuildthecomplexaccordingtothefollowingrules:

AnyblockthathasstyleZonitmustalsohavestyleWonit.

AnyblockadjacenttoonethathasonitbothstyleSandstyleXmusthaveonit

styleTandstyleZ.

NoblockadjacenttoonethathasonitbothstyleRandstyleZcanhaveonit

eitherstyleTorstyleW.

NoblockcanhaveonitbothstyleSandstyleQ.

20.Whichofthefollowingcanbethecompleteselectionofhousestyleonablock?

(A)Q,R,S(B)Q,S,X(C)R,T,Z(D)S,W,Z(E)T,X,Z