Nearly every day, you and I deal with small coins and
bank-notes (钞票). We need them for food and clothing. Whenever we want to buy
something, we always have to pay for it with money. But what would we do when
there were no metal coins and paper notes Thousands of years
ago, men did not have any money. The first men lived in caves (洞). Often they
were hungry and cold. They didn’t need any money. But soon they found that some
liked one kind of work better than another. But all of them had to eat and wear
clothes. And everyone needed tools and weapons (武器). So they started to trade
(做交易，进行贸易) with each other through buying things they needed or liked. People
have used all kinds of "money". First, they traded with salt, animals’ tails and
teeth... later they used a kind of metal named copper (铜). At last, people made
money lighter. They made it out of paper. We still use small
coins and paper notes today. Could there be an even easier way to carry money
Bank cards and Internet-banking are two such ways. Why did people not use copper as money any more Because ______.
A.it was too heavy
B.it was too light
C.it was not beautiful