下列方法中可用于与轴和轮毂周向固定的是( ) 。
D
键可用来轴上零件的周向固定,而其他选项可用于轴上零件的轴向定位。
Iftheoldmaximthatthecustomerisalwaysrightstillhasmeaning,thentheairlinesthatplytheworld’sbusiestairroutebetweenLondonandParishaveaflightontheirhands.
TheEurostartrainservicelinkingtheUKandFrenchcapitalsviatheChannelTunneliswinningcustomersinincreasingnumbers.InlateMay,itcarrieditsonemillionthpassenger,havingrunonlyalimitedservicebetweenLondon,ParisandBrusselssinceNovember1994,startingwithtwotrainsadayineachdirectiontoParisandBrussels.By1997,thecompanybelievesthatitwillbecarryingtenmillionpassengersayear,andcontinuetogrowfromthere.
FromJuly,EurostarstepsitsservicetoninetrainseachwaybetweenLondonandParis,andfivebetweenLondonandBrussels.Eachtraincarriesalmost800passengers,210oftheminfirstclass.
Theairlinesestimatethattheywillinitiallylosearound15%-20%oftheirLondon-ParistraffictotherailwaysonceEurostarstartsafullservicelaterthisyear(1995),with15trainsadayeachway.AsimilarservicewillstarttoBrussels.Thedamagewillbelimited,however,theairlinesbelieve,withpassengernumbersreturningtopreviouslevelswithintwotothreeyears.
Intheshortterm,thedamagecausedbythe1millionpeople-levelstravelingbetweenLondonandParisandBrusselsonEurostartrainsmeansthatsomeairservicesarealreadysuffering.Someofthemajorcarrierssaythattheirpassengernumbersaredownbylessthan5%andpointtotheirrivals-ParticularlyAirFrance-ashavingsufferedtheproblems.OntheBrusselsroute,therailwaycompanyhadlesssuccess,andtheairlinesreportanythingfromarounda5%droptonovisibledeclineintraffic.
Theairlines’optimismonreturningtrafficlevelsisbasedonhistoricalprecedent.BritishMidland,forexample,pointstoitsexperienceonHeathrowLeedsBradfordservicewhichsawpassengernumbersfoldby15%whenBritishRailelectrifiedandmodernizedtherailwaylinebetweenLondonandYorkshire.Twoyearslater,travelhadrisenbetweenthetwodestinationstothepointwheretheairlinewascarryingrecordnumbersofpassengers.
1.Britishairlinesconfideinthefactthat__.
A.theyaremorepowerfulthanotherEuropeanairlines.
B.theirtotallosswon’tgobeyondadropof5%passengers.
C.theirtrafficlevelswillreturnin2-3years.
D.travelingbyrailcannevercatchupwithtravelingbyair.
2.Theauthor’sattitudetowardsthedropofpassengersmaybedescribedas__.
A.worried.B.delightedC.puzzled.D.unrivaled.
3.Inthepassage,BritishRail(Para6)ismentionedto__.
A.provideacomparisonwithEurostar.
B.supporttheairlines’optimism.
C.provetheinevitabledropofairpassengers.
D.callforelectrificationandmodernizationoftherailway.
4.Therailway’sBrusselsrouteisbroughtforthtoshowthat__.
A.theEurostartrainserviceisnotdoinggoodbusiness.
B.theairlinescanwellcompetewiththerailway.
C.theEurostartrainserviceonlycausedlittledamage.
D.onlysomeairlines,suchasAirFrance,aresuffering.
5.Thepassageistakenfromthefirstofanessay,fromwhichwemaywellpredictthatinthefollowingparttheauthorisgoingto__.
A.praisetheairlines’clear-mindedness.
B.warntheairlinesofhigh-speedrailservices.
C.proposeareductionofLondon/Parisflights.
D.advisetheairlinestofollowBritishMidlandastheirmodel.
Paragraphs2and3explain________.