题目内容
在下图所示电路中，电源电压U=6V。若使电阻R上的电压U1=4V，则电阻R为（）。
查看答案
搜索结果不匹配？点我反馈
更多问题
Whichofthefollowingisnotadesignfeatureofhumanlanguage?（）
Questions11to15arebasedonthefollowingpassage.Scratchythroats,stuffynosesandbodyachesallspellmisery,butbeingabletotellifthecauseisacoldorflu(流感)maymakeadifferenceinhowlongthemiserylasts.TheAmericanLungAssociation(ALA)hasissuednewguidelinesoncombatingcoldsandtheflu,andoneofthekeysisbeingabletoquicklytellthetwoapart.That’sbecausetheprescriptiondrugsavailableforthefluneedtobetakensoonaftertheillnesssetsin.Asforcolds,thesoonerapersonstartstakingover-the-counterremedy,thesoonerreliefwillcome.Thecommoncoldandthefluarebothcausedbyviruses.Morethan200virusescancausecoldsymptoms,whilethefluiscausedbythreeviruses—fluA,BandC.Thereisnocureforeitherillness,buttheflucanbepreventedbythefluvaccine(疫苗),whichis,formostpeople,thebestwaytofighttheflu,accordingtotheALA.Butifthefludoesstrike,quickactioncanhelp.Althoughthefluandcommoncoldhavemanysimilarities,therearesomeobvioussignstolookfor.Coldsymptomssuchasstuffynose,runnynoseandscratchythroattypicallydevelopgradually,andadultsandteensoftendonotgetafever.Ontheotherhand,feverisoneofthecharacteristicfeaturesofthefluforallages.Andingeneral,flusymptomsincludingfeverandchills,sorethroatandbodyachescomeonsuddenlyandaremoreseverethancoldsymptoms.TheALAnotesthatitmaybeparticularlydifficulttotellwheninfantsandpreschoolagechildrenhavetheflu.Itadvisesparentstocallthedoctoriftheirsmallchildrenhaveflu-likesymptoms.Bothcoldandflusymptomscanbeeasedwithover-the-countermedicationsaswell.However,childrenandteenswithacoldorflushouldnottakeaspirinforpainreliefbecauseoftheriskofReyesyndrome(综合症)，ararebutseriousconditionoftheliverandcentralnervoussystem.Thereis,ofcourse,novaccineforthecommoncold.Butfrequenthandwashingandavoidingclosecontactwithpeoplewhohavecoldscanreducethelikelihoodofcatchingone.Ifchildrenhaveflu-likesymptoms,theirparents（）
应用溅渣护炉技术之后，炉底上涨的主要原因是（）。
Languageissaidtobearbitrarybecausethereisnologicalconnectionbetween（）andmeanings.
微信支付 
支付宝支付