.Unit1The Evolution of Transport交通工具的演化The evolutionof transporthas been closelylinked to the development of humankind throughout the earths history Transport s early function was to meet the basicneed of hauling food suppliesand buildingmaterials But with the formationof tribes ，then peoples ， and finallynations ，the societaland economic functionsof transport became more and more complex. At first there was mobility required for individuals， clans
