Unit1text1RoadBuildingTask1
therelationshipbetweenroadbuildingandeconomicdevelopment2
grainandcotton3
grewgraingrewcotton4
fastandconvenient5
totransportgrainandcottonTask1
Aboomingtradeingrainandcotton
BecauseoftherapidlygrowingpopulationandthelargenumberofimmigrantsfromEurope
ThefarmersgotlaborersfromAfrica
Becauseitwaseasyandcheaptotransportgoodsfromonplacetoanother
Theybuiltroadsandcollectedfees
Text2TheMississippiRiverinAmericaTask11
LakeItascainMinnesota2
about4,000kms
floodinginsummer4
floodways,dams,leveesandreservoirs5
holdingwaterandgeneratingelectricityTask2
21USstates
ItflowsfromtheNorthtotheGulfofMexico3
Theyareemptychannels
WhentheMississippiistoohigh,thefloodwaysareopenedandsomeofthewatercanflowintothefloodways
Theyareearthenwallsbuiltalongsideariver,hold