写一个100字左右的英文文章

What Is Money?

Most people don't spend much time wondering what money is, their major concern is how much they have, and how to get more. Usually, the question of what money IS arises only when money ceases to function properly. In economics (properly understood), the answer to the question - what is money? - consists of three words:
Money is a "medium of exchange"

That's all. Yet the conception of a "medium of exchange" ranks below only language (with its corollaries - speech and the written word) as the greatest intellectual discovery in history. Without language, the exchange of anything but the most rudimentary ideas is impossible. Without money, the production and exchange of anything but the most rudimentary goods and services is impossible. It is not difficult, or time consuming, or inefficient, it is IMPOSSIBLE