阅读理解。

Thereareaboutabillionbicyclesintheworldtwiceasmanyastherearecars.ButifKarlvonDraisthe

BaronofSauerbronn(1785-1851)hadn'tbeensuchalazypersonthebicyclemayneverhavebeeninvented

atall.

Althoughhehadaveryimportanttitle(andwasalsoaqualifiedandskillfulengineer)theBaronwasin

factaforestrangerinotherwordsagardenerwithresponsibilityforaverylargegarden.Hewasincharge

ofseveralhundredsquarekilometersofroyalgardenandforestsinCentralGermany.

In1817heinventeda"runningmachine"thatwouldhelphimgetroundtheestatemorequickly.The

machinewasmadeofwoodandhadtwowheelswhichwerethesamesize.Themachinehadawooden

frameandaleatherseat.Theriderrodethemachinelikeahorsebutwithhisfeetontheground.Afterrunning

forawhilehecouldthentakehisfeetoffthegroundandglidealong.Itwaspossibletochangedirectionby

controllingthefrontwheelbuttherewerenobrakes!In1863aFrenchmancalledPierreLallementattached

pedals(踏板)tothefrontwheelofabicycleandthemodernideaofabicyclewasborn.

Everygenerationseesnewdesignsandnewinterestinbicycles.Mountainbikesforexampletransformed

thewaypeoplethoughtaboutcyclingandintroducedanewsportwhichwasacceptedintotheOlympicsin

1996.

Newmaterialssuchastitaniumandcarbonfiberarenowusedtobuildstronglightweightmachinesand

combinedbrakeandgearsystemshavebeendeveloped.EnglishmanChrisBoardmanastonishedtheworldin

the1990swithhiscarbonfiberLotusbicyclewinningOlympicgoldinthe4000meterstrackpursuit(追逐)

inBarcelona.MorerecentlytheGreatBritainteamtookseveralmedalsattheAthensOlympics.

Formostpeoplehoweverthebicycleremainswhatithasalwaysbeen-apollution-freewayoftaking

exerciseandgettingfromAtoB.

1.Theunderlinedword"estate"inParagraph3refersto_____.

A.theBaron'sbighouse

B.themountainsinCentralGermany

C.theforestsneartheBaron'shouse

D.thelargegardenandforeststheBaroninchargeof