Transportationandcommunicationnetworksbringpeopletogether．Yetsometimespeoplethemselvescreatebarriers(障碍)totransportationandcommunication．Insomecountries，lawsstoppeoplefrommovingfreelyfromplacetoplace．Overthe
Transportationandcommunicationnetworksbringpeopletogether．Yetsometimespeoplethemselvescreatebarriers(障碍)totransportationandcommunication．
Insomecountries，lawsstoppeoplefrommovingfreelyfromplacetoplace．Overthecenturies，manygroupsofpeoplehavebeendeniedthefreedomtotravelbecauseoftheirrace，religion，ornationality．IntheMiddleAges，forexample，Jewswereoftenforbiddentomoveaboutfreelywithincertaincities．SouthAfrica’sgovernmentusedtorequireblackAfricanstocarrypasseswhentheytravelwithinthecountry．Somegovernmentsrequireallcitizenstocarryidentificationpapersandtoreporttogovernmentofficialswhenevertheymove．
Countriessetupcustomspostsattheirborders．Foreigntravellersmustgothroughacustomsinspectionbeforetheyareallowedtotravelinthecountry．Usuallytravellers havetocarryspecialpaperssuchaspassportsandvisas(签证)．Somecountriesevenlimitthenumberofvisitorstotheircountryeachyear．Othersallowtouriststovisitonlycertainareasofthecountry，ortheymayrequirethattravellersbewithanofficialguideatalltimesduringtheirstay．
Manyofthosebarrierstotravelalsoactasbarrierstocommunication．Whentwogovernmentsdisagreewitheachotheronimportantmatters，theyusuallydonotwanttheircitizenstoexchangenewsorideasfreely．Countriesoftentrytokeepmilitaryorlndustrialinformationsecret．
Today，peoplehavetheabilitytotravel，tocommunicate，andtotransportgoodsmorequicklyandeasilythaneverbefore．Naturalbarriersthatweredifficultordangeroustocrossahundredyearsagocannowbecrossedeasily．Thebarriersthatpeoplethemselvesmakearenotsoeasytoovercome．Butinspiteofallthedifferentkindsofbarriers，peoplecontinuetoenjoytravelandtheexchangeofgoodsandideas.
小题1:Choosethebesttitleforthepassage．A．ProgressofHumanSocietyB．RestrictionsonTransportationC．FunctionsofCommunicationD．BarriersMadebyPeople小题2:Theauthorusestheexamplesinthesecondparagraphtotellpeoplethat_______.A．travellershavetocarryspecialpaperssuchasv