英语专四考试阅读理解加分训练2018年英语专四考试阅读理解加分训练Actionisgoodmedicinetocurefear,hesitation,delaywillcontinuetonourishthefear.以下是小编为大家搜索整理的2018年英语专四考试阅读理解加分训练，希望能给大家带来帮助!更多精彩内容请及时关注我们应届毕业生考试网!Municipalsewageisofrelativelyrecentoriginasapollutant.Itwasfirstbroughttopublicattentioninthe19thcenturybyaLondonphysicianwhoshowedthatthecity'scholeraoutbreakhadbeencausedbyjustonecontaminatedwell.Eventhoughthecontaminationofdrinkingwaterbydiseasegermshasbeennearlyeliminatedinthiscountry,hundredsofcommunitiesarestilldischargingrawsewageintostreamsandrivers.?Whenweconsiderthatthissewagecontainseffluentsfromtoilets,hospitals,laundries,industrialplants,etc.,thenthepotentialofthepollutantsasahealthhazardisapparent.Theproblemofmunicipalsewagedisposaliscomplicatedbythefactthat,yearsago,mostcitiescombinedtheirstormandwastedisposalsewers.Manyofthesecombinedsystemsworkwell,butotherscannotcopewithsuddenheavyrains.Whensuchstormsoccur,watermixedwithsewagemayfloodanddisabletreatmentplantsunlessbypassed,untreated,intoastream.Ineithercase,thepeoplemayhavelittleprotectionforseveraldaysfromthesewastesthatmaycontaindiseasegerms.?Evenifadequatelytreatedtoeliminatethehealthhazard,sewageisaestheticallyundesirablebecauseofodorsandcolorsproduced.Detergentshaveposedaparticulardisposalproblem.Althoughthereisnoindicationthattheyareinjurioustohealth,theycancausefoaming,whichcanclogtreatmentplantsand,attheleast,spoilthescenicbeautyofstreams.?Ruralandsuburbanresidentsshouldbeawarethatseptictanksandcesspoolsareapotentialsourceofpollutiontogroundwatersupplies.Thisisespeciallytrueinthesuburbanareaswithahighpopulationdensityandwithnomunicipalsewagedisposalandtreatmentsystemavailable.Insomeareas,sewagedisposalisaccomplishedbycesspools.Soilresearchisfurnishingguidelinesformoreeffectiveandsaferuseofsystemssuchasthese.1.Thispassageisconcernedprimarilywiththe_____.A.problemsofwastedisposalB.dangersofdrinkingfromwellsC.turbidityofpollutedwaterD.outbreakofcholera2.TheauthormentionstheLondoncholeraepidemicto_____.A.provethatthe