Eachtunnelisroughlyroundandthelowerpartofthetunnelissomewhatflat.Thesurfaceoftheroadliesonthebase,whichismadeofconcreteandsteel.Thedrainagesystem(排水系统),justbelowtheroadsurfaceononeside,remo

　　Eachtunnelisroughlyroundandthelowerpartof

　　thetunnelissomewhatflat.Thesurfaceoftheroadlies

　　onthebase,whichismadeofconcreteandsteel.The

　　drainagesystem(排水系统),justbelowtheroadsurface

　　ononeside,removesanyextraliquid,particularlywater.

　　Intheeventoffire,thefiremain,whichismadeofsteel,

　　pipeswatertomanyfirehydrantstationsatregularintervals

　　alongthelengthofthetunnel.Thefiremainisatthesideofthetunnel,andattheleveloftheroadsurface.

　　Othersystemsinthetunnelwillincludeemergencyphones.1.Eachofthetunnelsunderconstructionis_____.A.eightkilometerslongandtwentymetreswide

　　B.eightkilometerslongandsixmetreswide

　　C.fourkilometerslongandtwentymetreswide

　　D.fourkilometerslongandsixmetreswide2.Whichpartofthetunnelinthediagramisusedtopipeoutextrawater?A.1.

　　B.3.

　　C.5.

　　D.6.3.Drivinginthetunnel,onecanknowthetrafficconditionsaheadthrough_____.A.thelights

　　B.theelectronicsigns

　　C.thetrucksandcars

　　D.theemergencyphones4.Thepassageismainlyabout_____.A.theconstructionofaroad

　　B.thedesignofaroad

　　C.theconstructionoftwotunnels

　　D.thedesignoftwotunnels