精品文档---下载后可任意编辑Unit 1 The Evolution of Transport 交通工具的演化The evolution of transport has been closely linked to the development of humankind throughout the earth’s history . Transport’s early function was to meet the basic need of hauling food supplies and building materials . But with the formation of tribes , then peoples , and finally nations,the societal and economic functions of transport became more and more complex
At first there was mobility required for individuals,clans,households,and animals to protect them against,and to escape from,the dangers of natural disasters and tribal aggressions,and in the search for the best places to settle.As tribal groups formed and gradually established their geographical identity,transport was increasingly needed to open up regions for development