Did you examine your paper money closely? See if you can locate a ＄5, ＄10, or ＄20 bill printed before 1964 and marked 'Federal Reserve Note' over the portrait. In the upperleft portion above the seal, a statement written in fine print says that the note is legal tender (法定货币) and that 'it is redeemable (可兑现的) in lawful money at the United States Treasury (美国财政部), or at any Federal Reserve Bank (联邦储备银行).' Does this mean that the bill is not lawful? At the bottom center the same bill says, 'Will pay to the bearer on demand X dollars.' Does this mean that your X-dollar bill is not X dollars? Much confusion exists about the real nature of money. Many people think that money has no value unless it is backed by gold or silver. They think that the Federal Reserve note is only a symbol for money, and that real money is the metal backing the note. Some people look on money as wealth and believe that it must have intrinsic (内在的) value. If we were to study the history of money, we would find that in different places and at different times a variety of things have been used as money. Cattle, shell, beads (珠子), tobacco leaves, and various metals—including iron, zinc (锌) , bronze (青铜) , and copper—have all been used as a basis of exchange. The precious metals, particularly silver and gold, have proved most satisfactory for this purpose and have been most commonly used in modem times. Until early 1968, the United States backed its Federal Reserve notes with 25 percent gold, but this did not mean that citizens could use gold as money or convert paper dollars to gold. Clearly, it is not what money is but what it does that is important. This passage is about______. A．the nature of money B．the face value of a bill C．the intrinsic value of money D．the lawfulness of money