对一个矩阵A＝（aij）m×n施行以下几种类型的变换，下列哪项不是矩阵的初等行变换（）。
A、交换A的某两行。B
本题考查初等变换的概念。选项B应该是用一个非零数乘A的某一行。
Thatradiocompanyissobigthatithasalotof____inforeigncountries.
Passage3
Questions11to15arebasedonthefollowingpassage:
UnliketheirAmericanorEuropeancounterparts,carsalesmeninJapanworkhardtogetabuyer.Insteadoflyinglazilyaroundshowroomswaitingforcustomerstodropby,manyJapanesecarsalesmenstillgoouttogetthem.Theywalkwearilyalongthestreetscarsdoor-to-door.Newcustomersarehuntedwithfruitandcakesontheirbirthdays.Butlifeisgettingtough,andnotjustbecausenew-carsalesarefalling.
WithmoreJapanesewomen(whooftencontrolthehouseholdbudget)goingouttowork,thesalesmenincreasinglyfindnobodyathomewhentheycall.Thatmeansanothervisitintheeveningortheweekend.Thentheyfaceanextraproblem:morepeople,especiallytheyoung,prefertochooseanewcarfromashowroomwheretheycancomparedifferentmodels.
Evenaslateasthemid-1980ssome90%ofnewcarsweresolddoor-to-door.Insomeruralareasmostnewcarsarestillsoldthisway.Butinthebigcitiesmorethanhalfthenewcarsarenowsoldfromshowrooms.
AlthoughinvestinginshowroomsisexpensivebecauseofthehighcostofJapaneseland,dealershavelittlechoice.AlaborshortageandhigheramongJapan’sworkforcearemakingitdifficulttohiredoor-to-doorsalesmen.MostofaJapanesecarsalesman’sworkingdayisspentdoingfavorsforcustomers,likearranginginsuranceorpickingupvehiclesforservicing,ratherthanactuallyselling.
Japan’sdoorstepcarsalesmenarenotabouttovanish.Thepersonalservicetheyprovideissodeep-rootedinJapanthattheyarelikelytooperatealongsidetheglitteringnewshowrooms.Thetwosystemsevencomplementeachother.Whatincreasinglyhappensisthattheshowroomattractstheinterestofapotentialbuyer,givingthefootsoresalesmenafirmleadtofollowupwithahomevisit.
11.Japanesecarsalesusuallydonotwaitatshowroomsforcustomerstodropby;instead,.
A.theysellcarsdoor-to-door
B.theybuypresentsfortheircustomers
C.theyenjoythemselvesinrecreationcenters
D.theygoouttodomarketresearches
12.Impliedbutstated:thecompetitionincarmarketis.
A.lightB.moderateC.fierceD.unfair
13.Youngpeopleliketobuyanewcar.
A.athomeB.fromashowroom
C.madeintheU.S.A.D.madeinJapan
14.ThesquadronofJapanesecarsalesmenisreducingbecauseof.
A.alaborshortage
B.higherexpectationsamongJapan’sworkforce
C.highcostland
D.bothAandB
15.Japanesecarsalesmentotheircustomersmanyfavorssuchas.
A.showingthemaroundinanexhibition
B.arranginginsurance
C.payingthemavisitonweekends
D.sellingolecarsforthem
Everyone____therighttohisownopinion.
PartIVTranslation
Asthesourceofaluminumisalmostinexhaustible,wecanexpectthatmoreandmoreuseswillbefoundforthisversatilemetal.(PassageTwo)
Theonlysoundsarebirdcallsandthesoftnoise________________(当水缓缓推动草时草所发出的)
