估算血液需求量的方法是所需血液的单位数大约是国家人口的5%。
1、正确正确
暂无解析
Ithink____importanttolearnEnglishwell.
Ihopemyfather____askmeaboutmymarks.
Our（）sensitivitydecreaseswithage.Byage60，mostpeoplehavelost40percentoftheirabilitytosmelland50percentoftheirtastebuds.
PARTVREADINGCOMPREHENSION
PASSAGEONE
(1)TheearliestsettlerscametotheNorthAmericancontinenttoestablishcoloniesthatwerefreefromthecontrolsthatexistedinEuropeansocieties.Theywantedtoescapethecontrolsplacedontheirlivesbykingsandgovernments,priestsandchurches,noblemenandaristocrats.ThehistoricdecisionsmadebythosefirstsettlershavehadaprofoundeffectontheshapingoftheAmerican
character.Bylimitingthepowerofthegovernmentandthechurchesandeliminatingaformalaristocracy,theycreatedaclimateoffreedomwheretheemphasiswasontheindividual.IndividualfreedomisprobablythemostbasicofalltheAmericanvalues.Byfreedom,Americansmeanthedesireandtheabilityofallindividualstocontroltheirowndestinywithoutoutsideinterferencefromthegovernment,arulingnobleclass,thechurch,oranyotherorganizedauthority.
(2)Thereis,however,apricetobepaidforthisindividualfreedom:self-reliance.ItmeansthatAmericansbelievetheyshouldstandontheirownfeet,achievingbothfinancialandemotionalindependencefromtheirparentsasearlyaspossible,usuallybyage18or21.
(3)AsecondimportantreasonwhyimmigrantshavetraditionallybeendrawntotheUnitedStatesisthebeliefthateveryonehasaequalchancetoenteraraceandsucceedinthegame.BecausetitlesofnobilitywereforbiddenintheConstitution,noformalclasssystemdevelopedintheU.S.
(4)Thereis,however,apricetobepaidforthisequalityofopportunity:competition.Ifmuchoflifeisseenasrace,thenapersonmustruntheraceinordertosucceed;apersonmustcompetewithothers.ThepressuresofcompetitioninthelifeofanAmericanbegininchildhoodandcontinueuntilretirementfromwork.Infact,anygroupofpeoplewhodoesnotcompetesuccessfullydoesnotfit
intothemainstreamofAmericanlifeaswellasthosewhodo.
(5)AthirdreasonwhyimmigrantshavetraditionallycometotheUnitedStatesistohaveabetterlife.Becauseofitsabundantnaturalresources,theUnitedStatesappearedtobea“landofplentywheremillionscouldcometoseektheirfortunes.Thephrase“goingfromragstoriches”becameasloganfortheAmericandream.Manypeopledidachievematerialsuccess.MaterialwealthbecameavaluetotheAmericanpeople,anditalsobecameanacceptedmeasureofsocialstatus.
(6)Americanspayaprice,however,fortheirmaterialwealth:hardwork.HardworkhasbeenbothnecessaryandrewardingformostAmericansthroughouttheirhistory.Insomeways,materialpossessionsareseenasevidenceofpeople’sabilities.BarryGoldwater,acandidateforthepresidencyin1964,saidthatmostpoorpeoplearepoorbecausetheydeservetobe.MostAmericanswouldfind
thisaharshstatement,butmanymightthinktherewassometruthinit.
(7)ThesebasicvaluesdonottellthewholestoryoftheAmericancharacter.Rather,theyshouldbethoughtofasthemes,aswecontinuetoexploremorefacetsoftheAmericancharacterandhowitaffectslifeintheUnitedStates.
1.Para.4seemstosuggestthat__________.
A.Americansarebornwithasenseofcompetition
B.thepressureofcompetitionbeginswhenonestartswork
C.successfulcompetitionisessentialinAmericansociety
D.competitionresultsinequalityofopportunities
2.WhichofthefollowingmethodsdoestheauthormainlyuseinexplainingAmericanvalues?
A.Comparison
D.Causeandeffect
C.Definition
D.Processanalysis
John'sscoreonthetestisthehighestintheclass;（）helastnight.
