Transportationandcommunicationnetworksbringpeopletogether．Yetsometimespeoplethemselvescreatebarriers(障碍)totransportationandcommunication．Insomecountries，lawsstoppeoplefrommovingfreelyfromplacetoplace．Over
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．travellershavetocarryspecialp
