ThepeoplewholivedinRomethousandyearsagowerealreadycomplainingaboutthenoiseintheircity.Theycouldn’tsleep,theysaid,withallthat(21)_______inthestreets.Forthem,noisewas(22)________adisturbance.Forusishasbecomeareal(23)_______.Weknowthatthesoundsofan(24)______cityareloudenoughtocauseseriousdamagetotheinhabitants’(居民)(25)______--intheUnitedStates,oneoutoftwentyhassufferedsomehearing(26)______.Andallovertheworldthesituationis(27)______allthetime,sincenoiseincreaseswiththepopulation.Ithasalsoincreasedenormouslyinthetwentiethcentury(28)____________.Weliveinanenvironmentsurroundedbyloudplanes,trucks,motorcycles,buses,electrictools,radios,etc.Thatroardayandnightupto90or100decibels(分贝).Unfortunately,thehumaneardoesnotjudgeclearly(29)_________________.Asoundtendecibelslouderthananotheroneisfeltastwiceasloud,wheninfactitistentimeslouder.Sincewecannotmeasuretheincreaseordecreaseofnoise,(30)__________________.