(A) Someday in the
future we may not need to have money in our pockets. Is life easier when
people don’t need to carry any money Is money heavy to carry Is it safe to
carry money Maybe in the future each of us will have only one small plastic
credit card (信用卡). We will use it to buy all the things we now buy with money.
We will not need money to pay for things. Of course we may
still have some of the same problems with cards that we now have with money.
Sometimes we lose money. Maybe we will lose the card. People steal money. Maybe
someone will take the card. Someone may even make a card that looks like our
card. Since we can’t buy anything without our card, the credit card may be no
better than currency. Is there something even easier to use
than credit cards All of us have a thumbprint (拇指纹 手印). No two thumbprints are
the same. Maybe someday the government will keep people’s thumbprints with a
number. No two people will have the same thumbprint or number. When we want to
buy something, we will put our thumbs on a machine or computer. Each store or
business will have one. Everyone’s thumbprint will be in the computers. It will
be very difficult to lose our thumbprint. It will be difficult for someone to
steal it or make one like it. The word "currency" (Para.2) most probably means ______.