如果由工质和环境组成的系统,只在系统内发生热量和质量交换关系,而与外界没有任何其他关系或影响时,该系统称为()。
A
A项,孤立系统是指与外界既无能量交换又无物质交换的系统;B项,开口系统是指与外界有物质交换的系统;C项,刚体系统与本题无关,属于力学的范畴;D项,闭口系统是指与外界无物质交换的系统。
GriffithworkedforafirmthatspecializedineconomicdevelopmentinWashingtonD.C.becausesheneededmoneytopayforherdebt.
Thissupermarketdevelopedrapidlyunderhis_____.
Passage3
Questions11to15arebasedonthefollowingpassage:
TheideaofaspecialdaytohonormotherswasfirstputforwardinAmericain1907.twoyearslaterawoman,Mrs.JohnBruceDodd,inthestateofWashingtonproposedasimilardaytohonortheheadofthefamily—thefather.Hermotherdiedwhenshewasveryyoung,andherfatherbroughtherup.Shelovedherfatherverymuch.
InresponsetoMrs.Dodd’sideathatsameyear—1909,thestategovernorofWashingtonproclaimed(宣布)thethirdSundayinJuneFather’sDay.TheideawasofficiallyapprovedbyPresidentWoodrowWilsonin1916.in1924,PresidentCalvinCoolidgerecommendednationalobservanceoftheoccasion“toestablishmoreintimate(亲密)relationsbetweenfathersandtheirchildren,andtoimpressuponfathersthefullmeasureoftheirobligations.”TheredorwhiteroseisrecognizedastheofficialFather’sDayflower.
Father’sDaytooklongertoestablishonanationalscalethanMother’sDay,butastheideagrainedpopularity,tradesmenandmanufacturersbegantoseethecommercialpossibilities.Theyencouragedsonsanddaughterstohonortheirfatherswithsmallthank-youpresents,suchasatieorpairofsocks,aswellasbysendinggreetingcards.
DuringtheSecondWorldWar,AmericanservicemenstationedinBritainbegantorequestFather’sDaygreetingcardstosendhome.ThisgeneratedaresponsewithBritishcardpublishers.ThoughatfirsttheBritishpublicwasslowtoacceptthisratherartificialday,it’snowwellcelebratedinBritainonthethirdSundayinJuneinmuchthesamewayasinAmerica.
Father’sDayseemstobemuchlessimportantasoccasionthantheMother’sDay.Notmanyofthechildrenoffertheirfatherssomepresents.ButtheAmericanfathersstillthinktheyaremuchbetterfatedthanthefathersofmanyothercountries,whohavenotevenadayfortheirsakeinnameonly.
11.WhendidFather’sDayofficiallybegintohavenationalpopularity?
A.1907B.1909C.1916D.1924
12.WhofirststartedtheideaofholdingtheFather’sDay?
A.Mrs.JohnBruceDoddB.Mrs.JohnBruce’sMother
C.ThegovernmentofWashington.D.Somebusinessmen.
13.WhatflowerwillbepopularonFather’sDay?
A.LilyB.WaterLilyC.RedroseorwhiteroseD.Sunflower.
14.Whichstatementistrue,aaccordingtothispassage?
A.IttookevenlongerforMother’sDaytogainnationalpopularity.
B.ThebusinessmenhelpedtomakeFather’sDaypopular.
C.Father’sDayisonlycelebratedinAmerica.
D.Father’sDayisonlyatrickofthebusinessmentomakemoney.
15.WhatwasthefirstreactionoftheBritishpublishingtowardsFather’sDay?
A.Theythoughthighlyofitandaccepteditatonce.
B.Theyjustaccepteditatoncewithoutanyhesitation.
C.Theyjustthoughtitajoke.
D.Theythoughtitwastooartificialandtookalongtimetoaccept.
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