1、make it rain 向天空撒錢
2、錢的三個主要功能:
medium of exchange(物物交換的中介), unit of account(計量單位), and store
of value(價值的儲存功能)
第一個功能是最重要的:物物交換的中介
humans created a commodity that they would agree upon ahead of time could be used in exchange, and that commodity is money.
3、古時候人們還會這樣進行物物交換:今天我向你借了五瓶啤酒,將來某一天我再還你,這就存在關乎信用的問題了。