阅读下面短文，从每题所给的四个选项中选出最佳答案.

OverheadBridges

OverheadbridgesarefoundinmanypartsofBeijingespeciallyinplaceswheretrafficisveryheavyandcrossingtheroadisdangerous.

Thepurposeofthesebridgesistoenablepedestrians（行人）tocrossroadssafely.Overheadbridgesareusedinverymuchthesamewayaszebracrossing.Theyaremoreefficientalthoughlessconvenientbecausepeoplehavetoclimbupalongflightofsteps.Thisisinconvenientespeciallytoolderpeople.Whenpedestriansuseanoverheadbridgetheydonotholduptraffic.Howeverwhentheycrossabusyroadusingazebracrossingtrafficisheldup.Thisiswhythegovernmenthasbuiltmanyoverheadbridgestohelppedestriansandtokeeptrafficmovingatthesametime.

ThegovernmentofBeijinghasspentalargeamountofmoneyinbuildingthesebridges.Fortheirownsafetypedestriansshouldbeencouragedtousetheminsteadofriskingtheirlivesbydashingacrosstheroad.Oldpeoplehowevermayfinditalittledifficulttoclimbupanddownthestepsbutitisstillmuchsaferthanwalkingacrosstheroadwithallthedangerofmovingtraffic.

Overheadbridgesserveaveryusefulpurpose.Pedestriansbotholdandyoungshouldmakeitahabittousethem.Thiswillpreventunnecessaryaccidentsandlossoflife.

（1）Whatistheadvantageofoverheadbridgesmentionedinthispassage?

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A.Tallertruckscanpassunderthem.

B.Pedestrianscanclimbupandhaveaviewofthecity.

C.Theyaresaferforpedestriansandcankeeptrafficmovingatthesametime.

D.Theyareeasierandmoreconvenientforthepedestrians.

（2）Whichofthefollowingstatementsistrueaccordingtothepassage?

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A.OverheadbridgesarefoundineverypartofBeijing.

B.OverheadbridgesareonlyfoundincenterofBeijing.

C.OverheadbridgesarefoundinmanypartsofbigcitiesinChina.

D.Overheadbridgesarefoundinplaceswheretrafficisheavy.

（3）Theunderlinedwordsazebracrossingprobablymean________.

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A.asafeplaceacrossaroadforpedestrianstowalkacrosstheroad

B.awildanimalfromAfricathatlookslikeahorsewithbroaddark