支配虹膜环形肌的是

A、N受体
B、M受体
C、α受体
D、β受体
E、多巴胺受体
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正确答案:

B

答案解析:

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Yesterdaywassucha____daywedecidedtogoforadrive.

A、glorious
B、dynamical
C、avenue
D、invitation

.IfyouhavereallybeenstudyingEnglishforsolong,it’sabouttimeyou_____abletowritelettersinEnglish.

A、shouldbe
B、were
C、mustbe
D、are

InwhatwaydoesLauraLenox-Conynghammakeherliving?

A、Bytakingphotographsformagazines
B、Bymarringarichman
C、Bysublettingtheloungesofa-bedtoherbrother
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Passage2

Questions6to10arebasedonthefollowingpassage:

Whenaluminumwasfirstproducedaboutahundredandfiftyyearsago,itwassodifficulttoseparateformtheoresinwhichitwasfoundthatitspricewashigherthanthatofgold.Thepriceremainedhighuntilanewprocesswasdiscoveredforrefiningthemetalwiththeaidofelectricityapproximatelythreequartersofacenturylater.Thenewmethodwassomuchcheaperthataluminumbecausepracticalformanypurposes,oneofwhichwasmakingpotsandpans.

Aluminumislightweight,rustproofandeasilyshapedintodifferentforms.Bymixingitwithothermetals,scientistshavebeenabletoproduceavarietyofalloys,someofwhichhavethestrengthofsteelbutweighonlyonethirdasmuch.

Today,theusesofaluminumareinnumerable.Perhapsitsmostimportantuseisintransportation.Aluminumisfoundintheengineofautomobiles,inthehullsofboats.Itisalsousedinmanypartsofairplanes.Infact,thehuge“airbus”planeswouldprobablyneverhavebeenproducedifaluminumdidnotexist.Bymakingvehicleslighterinweightaluminumhasgreatlyreducedtheamountoffuelneededtomovethem,Aluminumisalsobeingusedextensivelyinthebuildingindustryinsomecountries.

Sincealuminumissuchaversatile(多用的)metal,itisfortunatethatbauxite(铝土矿),whichisoneofitschiefsources,isalsooneoftheearth’smostplentifulsubstances.Asthesourceofaluminumisalmostinexhaustible,wecanexpectthatmoreandmoreuseswillbefoundforthisversatilemetal.

6.Thepriceofaluminumwassharplyreducedwhenpeoplediscoveredanewrefiningprocesswiththeaidof.

A.windB.solarenergyC.hydraulicpowerD.electricity

7.Aluminumis.

A.lightweight,rustproofbutnoteasilyshapedintodifferentforms

B.heavyweight,rustproofandeasilyshapedintodifferentforms

C.lightweight,rustproofandeasilyshapedintodifferentforms

D.lightweightandeasilyshapedintodifferentformsbutitiseasytobecomerusty

8.WhichofthefollowingisNOTtrue?

A.Aluminumiswidelyusedintransportation.

B.Aluminumisalsousedinmanypartsofairplanes.

C.Aluminumisbeingusedextensivelyinthebuildingindustry.

D.Aluminumisnotusedinitspureform.

9.Aluminumisfoundonearthmostlyintheformof.

A.puremetalB.bauxiteC.goldD.liquid

10.Whatisthepassagetalkingabout?

A.Thefeaturesofaluminumanditsfunctions.B.Theprocessofaluminum.

C.Thediscoveryofaluminum.D.Thepromisingfutureofaluminum.

Recentresearchhasclaimedthatanexcessofpositiveionsintheaircanhaveanilleffectonpeople’sphysicalorpsychologicalhealth.Whatarepositiveions?Well,theairisfullofions,electricallychargedparticles,andgenerallythereisaroughbalancebetweenthepositiveandthenegativecharged.Butsometimesthisbalancebecomesdisturbedandalargerproportionofpositiveionsarefound.Thishappensnaturallybeforethunderstorm,earthquakeswhenwindssuchastheMistral,HamsinorSharavareblowingincertaincountries.Oritcanbecausedbyabuild-upofstaticelectricityindoorsfromcarpetsorclothingmadeofman-madefibres,orfromTVsets,duplicatorsorcomputerdisplayscreens.

Whenalargenumberofpositiveionsarepresentintheairmanypeopleexperienceunpleasanteffectssuchasheadaches,fatigue,irritability,andsomesensitivepeoplesuffernauseaorevenmentaldisturbance.Animalsarealsoaffected,particularlybeforeearthquakes,snakeshavebeenobservedtocomeoutofhibernation,ratstofleefromtheirburrows,dogshowlandcatsjumpaboutunaccountably.ThishasledtheUSGeographicalSurveytofundanetworkofvolunteerstowatchanimalsinanefforttoforeseesuchdisastersbeforetheyhitvulnerableareassuchasCalifornia.

Conversely,whenlargenumbersofnegativeionsarepresent,thenpeoplehaveafeelingofwell-being.Naturalconditionsthatproducetheselargeamountsarenearthesea,closetowaterfallsorfountains,orinanyplacewherewaterissprayed,orformsaspray.Thisprobablyaccountsforthebeneficialeffectofaholidaybythesea,orinthemountainswithtumblingstreamsorwaterfalls.

Toincreasethesupplyofnegativeionsindoors,somescientistsrecommendtheuseofionisers:smallportablemachines,whichgeneratenegativeions.Theyclaimthationisersnotonlycleanandrefreshtheairbutalsoimprovethehealthofpeoplesensitivetoexcesspositiveions.Ofcourse,therearethedetractors,otherscientists,whodismisssuchclaimsandareskepticalaboutnegative/positiveionresearch.Thereforepeoplecanonlymakeuptheirownmindsbyobservingtheeffectsonthemselves,oronothers,ofanegativerichorpoorenvironment.Afterallitisdebatablewhetherdependingonseismicreadingstoanticipateearthquakesismoreeffectivethanwatchingthecat.

1.Whateffectdoesexceedingpositiveionizationhaveonsomepeople?

A.Theythinktheyareinsane.

B.Theyfeelratherbad-temperedandshort-fussed.

C.Theybecomeviolentlysick.

D.Theyaretootiredtodoanything.

2.Inaccordancewiththepassage,staticelectricitycanbecausedby___.

A.usinghome-madeelectricalgoods.

B.wearingclothesmadeofnaturalmaterials.

C.walkingonartificialfloorcoverings.

D.copyingTVprogramsonacomputer.

3.Ahighnegativeioncountislikelytobefound___.

A.nearapoundwithawaterpump.

B.closetoaslow-flowingriver.

C.highinsomebarrenmountains.

D.byarotatingwatersprinkler.

4.Whatkindofmachinecangeneratenegativeionsindoors?

A.Ionisers.

B.Air-conditioners.

C.Exhaust-fans

D.Vacuumpumps.

5.Somescientistsbelievethat___.

A.watchinganimalstoanticipateearthquakesismoreeffectivethandependingonseismography.

B.theunusualbehaviorofanimalscannotbetrusted.

C.neitherwatchingnorusingseismographsisreliable.

D.earthquake

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