直流电动机改变电枢电压调速，电动机励磁应保持为额定值。当工作电流为额定电流时，则允许的负载转矩不变，所以属于恒转矩调速。
1、正确正确
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完型填空(本大题共10小题，每小题1分，共10分)从选项中选择一个最适合短文的选项，错选、多选或未选均无分。
Joggingisbecomingoneofthe___21___growingactivitiesinthenation.Morepeoplearestartingjogeachyear.This,however,isarecentoccurrence.Itwasnotlongago__22____joggerswereraresight.Somepeoplethoughtthattheylookedquitestrange.As__23____peoplebeganjoggingthesightofthembecamemorecommon.Therearemanyreasons___24___apersontotakeupjogging.First,itisagoodformofexercise.Thisis__25____itinvolvestheuseofmanypartsofthebody.Theexercisingoftheheartisofgreatbenefit.Thisisoneofthemostimportantpartsofthehumanbody.Iftheheartdoesnotgettheneededexercise,seriousproblemscanoccur.___26___reasonforjoggingisforenjoyment.___27___beinggoodforpeople,itcanalsobeverymuchfun.Partofthefunofjoggingcomesfromtheopportunityitprovidesformeetingotherpeoplewhoenjoyit.One___28___thatshouldbeconsidered___29___apersontakesupjoggingasaformofexerciseofenjoymentisthatitisnotforeveryone.Peopleshouldfirstcheck30theirdoctorsandbepreparedtofindanotherformofexerciseifjoggingisnotrecommended.
21.A.fastestB.quickestC.mostD.best
22.A.whenB.whileC.thatD.as
23.A.manyB.thoseC.moreD.the
24.A.ofB.withC.forD.in
25.A.thatB.whyC.reasonableD.because
26.A.AB.OtherC.TheotherD.Another
27.A.ExceptB.ExceptforC.BesidesD.Regardlessof
28.A.matterB.eventC.thingD.occurrences
29.A.ofB.thatC.whatD.when
30.A.outB.overC.onD.with
以互联网上传输的和用户接收到的计算机信息数据单位“比特”的数量为收税依据的征税方案称为（）
英译汉：Evenasexchangesemergetoenablerichinteractionamongcompanies,businessesarelookingforwardtotheInternettoenabletheadoptionoftrulydynamicpricing.Onesolutionisemergingintheformofbots,softwarethatservesasanagentactingonbehalfofaspecificuserorapplication.Advancingbottechnologyenablesdynamic,automated,real-timeinteractionbetweenbuyersandsellers,allowingsellerstocapturethetruevalueoftheirgoodsinthemarket.
承担责任的adj.r_______________
下列属于电子证据特征的有（）
