Thesenseofsoundisoneofourmostimportantmeansofknowingwhatisgoingonaroundus.Soundhasawastedproduct,too,intheformofnoise.Noisehasbeencalledunwantedsound.Noiseisgrowinganditmaygetmuchworsebeforeitgetsanybetter.Scientists,forseveralyears,havebeenstudyinghownoiseaffectspeopleandanimals.Theyaresurprisedbywhattheyhavelearned.Peaceandquietarebecominghardertofind.Noisepollutionisathreatthatshouldbelookedatcarefully.Thereisasayingaboutitbeingsonoisythatyoucan’thearyourselfthink.Doctorswhostudynoisebelievethatwemustsometimeshearourselvesthink.Ifwedon't,wemayhaveheadaches,otherachesandpains,orevenworsementalproblems.Noiseaddsmoretension(紧张)toasocietythatalreadyfacesenoughstress.Butnoiseisnotanewproblem.InancientRome,peoplecomplainedsomuchaboutnoisethatthegovernmentstoppedchariots(四轮马车)frommovingthroughthestreetsatnight!Waysofmakinglessnoisearenowbeingtested.Thereareevenlawscontrollingnoise.Wecannotreturntothe"goodolddays"ofpeaceandquiet.Butwecanreducenoise--ifweshoutloudlyenoughaboutit.Whyarescientistssurprisedbythefindingsintheirnoisestudy?
A
Because the world is becoming more and more noisy.
B
Because they have learned that noise is also a kind of pollution.
C
Because noise is an unwanted waste for human beings.
D
Because people knew little about the danger of noise before.
