Page 1
Long ago, people often traded goods directly, such as grain for cloth or eggs for tools.
很久以前，人们常常直接用东西换东西，比如用粮食换布，用鸡蛋换工具。正文预览
Page 2
Barter could fail when one person had grain and wanted shoes, but the shoemaker did not need grain at that moment, which made direct trade awkward.
如果一个人手里有粮食想换鞋子，可做鞋的人当时并不需要粮食，直接交换就会卡住，这正是以物换物常常麻烦的地方。
Page 3
Money became useful because it gave people a shared way to measure value and exchange many different things more easily.
钱之所以有用，是因为它给了大家一个共同衡量价值的方法，让不同东西的交换变得更容易。
Page 4
At first, different places used shells, metal, or other objects that many people agreed could stand for value.
一开始，不同地方会用贝壳、金属或别的物品来代表价值，只要很多人都认可就能使用。
Page 5
Coins and paper money later made trade easier, because they were easier to count, carry, and compare than bags of goods.
后来出现的硬币和纸币让交易更方便，因为它们比一大堆实物更容易计算、携带和比较。
