Besidescontainingattractiveflowers,treesandotherplantsthatbeautifythecommunity,eco-friendlyraingardensarehealthyfortheenvironmentandthepeoplelivingandworkingnearby.Araingardenisnotverydifferentfromatraditional

　　Besidescontainingattractiveflowers,treesandotherplantsthatbeautifythecommunity,eco-friendlyraingardensarehealthyfortheenvironmentandthepeoplelivingandworkingnearby.

　　Araingardenisnotverydifferentfromatraditionalgarden.Itisjustafarmoreeco-friendlygarden.Usuallyitisbuiltlowerthantheground.Raingardensmakesmartuseofrainandstormwaterbytemporarilyholdingwaterfromrainandstormsandlettingitsoak（浸人）slowlyintothegroundbeforeitrunsintostreamsorentersthepublicdrinkingwatersupply.

　　Thus,araingardenkeepsthewater,allowingittobeusedasneededbyplantsintheraingarden,ratherthanflowingimmediatelyintonearbystreamsandgoingunused.Thewaterwillsoakslowlyintothegroundwithinadayortwo.Thiscreatesanadvantagethattheraingardendoesnotallowmosquitoestobreed.Thisisasimple,attractive,andeco-friendly“green”waytotreatstormwater.

　　What’smore,plantingaraingardenhelpsreducepollutionandimprovetheenvironment.Withoutusingexpensivemachineryandchemicals,raingardensremoveharmfulchemicalsintherainwaterandcutdownontheamountofpollutionreachingstreamsandriversbyupto30%.

　　Nativeplantsarerecommendedforraingardensbecausetheyaremoreusedtothelocalsclimatem,soil,andwaterconditions.Theymayattractlocalwildlifesuchasnativebirds.Wateryourraingardenimmediatelyafterplantingandonceaweek,unlessyouhavehadatleastaninchofrainduringtheweek.Oncethenativeplantsestablishthenecessaryrootsystem,itwillrequirelittlecare.

　　Often,localgovernmentsandprivatebusinessesdeveloplargeraingardensintheiryardsandinpublicparksasawaytoimprovetheenvironmentandsolvefloodingproblems.However,youdon’tneedtobeaprofessionalenvironmentalengineertocreatearaingarden.Aslongasyou’reeco-conscioushomeowners,youcanhelptheenvironmentbybuildingsmallerraingardensinyouryards.

　　小题1:Whichofthefollowingistheeco-friendlyfunctionofraingardensdiscussedinParagraph4?A．Theycankeeptherainandstormwater.B．Theycanhelpreducethepollutionproblem.C．Theycanbehealthyforthepeoplearound.