【Duringthelasttwentyyearstherehasbeenincreasingconcernwiththequalityoftheenvironment.Alongwithairandwaterpollutionsnoisespollutionhasbeenrecognizedasaseriouspollutant.Asnoiselevelshaverisentheeffectsofn】

Duringthelasttwentyyearstherehasbeenincreasingconcernwiththequalityoftheenvironment.Alongwithairandwaterpollutionsnoisespollutionhasbeenrecognizedasaseriouspollutant.Asnoiselevelshaverisentheeffectsofnoisehavebecomemoreapparent.

Noiseisdefinedas"unwantedsound".Causesofnoisepollutionincludetrafficaircraftrockbandsbarkingdogstelevisionsgarbagetrucksandnoisefromneighborsvoicesalarmsandwatercrafts.StudiesshowthatoverfortypercentofAmericansaredisturbedathomeorlosesleepbecauseofnoisepollution.

Noisehasbadeffectsonpeopleandtheenvironment.Noisecauseshearinglossinterferes(妨碍)withhumanactivitiesathomeandworkandisinvariouswaysdangeroustopeople'shealthandwellbeing.

Whenwethinktalklistentomusicorsleepweneedquiet.Evenlowlevelsofnoisecanbeannoyingorfrustrating.Suddenincreasesinvolumecanmakesoundsannoying.Thequieterthebackgroundisthemorepenetratinganoisecanbe.

Noisecanalsomakeinstructionsorwarningunclearresultinginaccidents.Loudernoiseburstscanbemoredisruptive(破坏性).Continuedstresscanleadtohighbloodpressurewhichisthemajorcauseofsomediseases.

Longexposuretonoiselevelsaboveeight-fivedecibels(分贝)candamageinnercellsandleadtohearingloss.Noisecanresultintheinvoluntaryfearresponseandcancauseadrenaline(肾上腺素)tobepumpedintothebloodstreamtheheartratetoquickenmusclestotensebreathingtoincreaseandthedigestivesystemtoslowdown.

Localgovernmenthastheresponsibilitytofightnoisepollution.Forexampleitcanregulatethespeedoftrainsthroughtheircommunity.Ontheotherhandaresponsiblecitizenwillnevermakenoisepollutionwhereverheis.

1.Howmanykindsofenvironmentalpollutionarementionedinthetext?

A.Two B.Three C.Four D.Five

2.Accordingtothetextnoisepollutionmaybecausedby .

A.partiesandmeetings B.zoosandtheaters

C.schoolsandfactories D.vehiclesandanimals

3.Whatdoestheunderlinedword"penetrating"inparagraph4me